A derivitave of the word wheremst, but replacing the where with who. So instead of where, what, why, and how, it is instead; who, what, why, and how.
Person 1: whomst has stolen my milk?
Person 2: bob, because he didnt have any, he took it from the fridge, and your milk.
Not a real word; made by the internet/ an internet slang. Came into usage after a meme, literally. Its supposed to be short of "who amongst (you/us)" Often used as joke in a conversation.
(Into a groupchat)
J : Whomst hath summoned the almighty one?
K : we tagged you, you idiot:|
J : Sighh speak peasant-!
A combination of the words "whom" and "did" creating the word "whomst".
Whomst fucking opened the chip bag from the bottom.
A plural form of whom.
Note that contractions can be combined.
Whomst've'd been pranked before?