More importantly I think he'd have protections against stabbings/piercing/etc, kinda like the impervius charm but for solid objects.
There probably have been attempts to assassinate him by surprise before so he'd have precautions in place.

 

Paint a fake door in one of the corridors and add several signs of free wizard candy pointing to it. When Dumbledore sees it and tries to run inside he will smack his face against the wall and fall backwards, activating a portkey that will make an anvil appear a few meters over his head. To make the plan foolproof, tie some erumpent horn fluid vials to the anvil.

(Yup, this canon arc read like a Roadrunner-Coyote episode, so why the heck not?)

 

Spoiler

Hire the most nihilistic, depressing person you can find (Draco still has money) and have them walk up to Dumbledore and calmly explain why life is pointless.

Actual strategy: Hire a vampire to bite him. Too risky? Offer him lemon drops with a single cyanide pill (carefully worked to look like a lemon drop, or an every-flavor jelly bean).

Nope, Dumbledore's too fucking OP for that!

Set invisible, poisonous gas inside Hogwarts. (Preferably cyanide)

Nope! Headmaster is too badass for that.

Assassin polyjuiced as someone he trusts (has to be a very convincing act).

Nope. Legilimency takes care of that (or does it? I'm still unsure on whether he stopped using it on students because of his conscience).

I'm rambling.

(Is the motherfucker that hard to kill? Apparently.)

Get some felix felicis, a substantial amount (it would be expensive but maybe Draco can afford it(?)). Give it to the highest-tier death eaters and send them his way (Voldemort too, but he'd probably(?) be too prideful for that).

Kill with axe.

Kill with cutlery.

Imperio Snape(somehow) and as Dumbledore is getting a potion from him, ensure it has cyanide in it or a hopefully deadlier poison.

Imperio a muggle so that he runs over Dumbledore.

(Ooh, I love this one!) Put Dumbledore on a broomstick cursed to fly upward super fast (and for forever). It can't be removed once it's attached to him. He can't apparate away (for some reason) and he'll eventually just suffocate in space. Also disables portkeys.

(You can't kill him.) Realistically catching him in a scenario similar to the Half-Blood Prince's scene is beyond unlikely (He's probably had attempts before but I could be wrong).

I argue your best bet is to just play out the same scenario that happens in the Half-Blood Prince. Snape's AK killed him.

Or you have the nerve on the Astronomy Tower, and you muster up the will to shoot it at Dumbledore.

 

Something something hatch a basilisk in the Room of Requirement something something enchanted mirror something something petrify everyone in the school something something finish it off.

 

Step 1 - buy an adult mandrake
Step 2 - Imperius a hogwarts house elf
Step 3 - choose a place you know Dumbledore will be - his office maybe, or his sleeping quarters
Step 4 - Get the house elf to wear earmuffs and pop in to drop the mandrake in his lap with a sonorous charm applied to it.
Step 5 - ??? Profit.

 

Man.

For at least two years I've had an idea in my notes doc to run a quest called "Dumbledore Must Die" here on DLP where the readers were Draco trying to do exactly this.

Now I don't have to!

 

Nothing wrong with two threads about the same idea

 

Make it a groundhog day loop where Draco goes progressively more mad with each failing and sit back and profit.

 

Step 1: Get letter from goblins saying you are heir to *insert family* that Dumbledore kept from you

Step 2: Go to the amazing and powerful Amelia bones and tell her and the media

Step 3: Dumbledore loses positions, gets job as bouncer for hogs head

Step 4: He gets depressed and ends his own life

Step 5: wait a second..... you aren’t Harry Potter in this scenario

Edit: wow, this was a low effort shitpost. Apologies.

 

Get that time turner from Cursed Child and kill Dumbledore when he's just a baby?

 

Hiring male stripper? or Draco bends over and think about England?
Such excitement at his age probably isn't good of his hurt, who knows maybe he will pop a vein.

Or waiting, Dumbledore was dying anyway.

Incriminating his godfather (is that canon?) in a way that shock Dumbledore and he suffers heart attack?

 

1. Waffle around for a year
2. Dumbledore dies of Horcrux poisoning
   
3. Truly a Great Victory for House Malfoy!

 

• Buy a cursed necklace
• Place a random girl under the imperious curse
• Instruct her to give the necklace to Dumbledore

This plan is flawless. Nothing can go wrong.

 

I say go all out. You know that Voldemort will reward you if you kill Dumbledore, and even if you get caught, you'll be expecting the Dark Lord to spring you out of Azkaban or to take over the Ministry, and set you free. So here's the plan:
Put two or three senior students under the imperious curse ( preferably ones with good grades in DADA). Force one of the students to start chocking on his food, seriously have the guy play it up. As Dumbledore is at least nominally a good headmaster and person, it is very likely that he will come down to the table and try to help the student. As the student will be forcing himself to choke on his food, acting and maybe attempting to swallow his own tongue, it is unlikely that a simple spell would solve the problem. When Dumbledore is beside the student, have the two other guys under the imperious curse cast explosive curses at Dumbledore and at the table, hopefully killing him or injuring him. If this attack fails, then it is likely that at least some students will be injured. As this would essentially amount to an act of terrorism, the Aurors and Healers from St Mungo's would likely be called. If Malfoy was in collaboration with other senior Deatheaters, then this would be the perfect time to slip them in.

Either the attack kills or injures Dumbledore, creates general fear and hysteria in the Wizarding World or allows Deatheaters to slip into Hogwarts.

 

Easy solution, if narratively displeasing.

Practice imperius curse and memory charm till brought to a reasonable degree of competence.

Find a gullible looking group of people, preferably Gryffindors.
Does not havethave to be a snap decision, take some time to stal-research.

Imperius two people from the above mentioned group, order one to act weird for a day.
The next day, order the other to suggest to the group that the first dude might be imperiused, and it has to be brought to Dumbledore.

Remove imperius from the one who gave the imperius theory, when alone, and memory charm so he doesn't remember he was ever imperiused.

We now have a single imperiused individual, and a group of concerned friends who will bring him to Dumbledore.

Acquire magical explosives or use equivalent charm, potentially from Snape, who is oathbound to help. Make sure difficult to detect.

Suicide bombing ftw.

 

Alternatively imperius chain half of Hogwarts (A imperiuses B, who imperiuses C, and so on) and teach all of them some basic dark spell that's lethal but easy to learn.

Sure, Dumbledore might be able to defend himself, but he'd probably have to slaughter kids to do it, and as such might just let himself die, especially in light of his already reduced life span.

Is this narratively, conceptually or logically pleasing.. no. But imperius chaining is canon, so I guess it's a possible solution, although I do prefer the ahem non-consensual kamikaze approach.

 

I think that the suggestion Dumbledore couldn't non-lethally handle a group of school children seriously underestimates Dumbledore.

 

Imperius chaining half of Hogwarts would also require teaching half of Hogwarts to use the Imperius Curse, so your chances of not getting caught before you have your army ready are pretty much nil.

 

With any kind of open threat he could easily get away (he can make portkeys in Hogwarts) and the ability to get away allows him to assess the situation. I would think he could determine who's under the control of whom using Legilimency.

 

Also, good luck trying to convince Snape to brew some explosive potion for you. He is oath-bound to 1) watch over Draco, 2) protect him from harm, and 3) kill Dumbledore in his stead if he's not able. Never in all that is he forced to actually help Draco. In fact "protect him from harm" might very well include "don't let him go near explosives."

And Dumbledore doesn't even need Portkeys, he's got Fawkes.