op

Etymology 1

noun

1. (informal) Clipping of operation.
   My mother's going in for her knee op today.
2. (informal) Clipping of operator">operator.
   1. (informal) An amateur radio operator">operator.
   2. (Internet) An operator">operator on IRC, who can moderate the chat channel, ban users, etc.
3. (Internet slang, chiefly in the plural) Clipping of opinion.
   Ops on my new drawing?
4. (chiefly attributive) Ellipsis of op art.
   an op painting; op artworks

verb

1. (transitive, Internet) To promote (an IRC user) to an operator.
   True, better clients will remember that a person had a voice before they were opped and will return the + when they are deopped, but that doesn't solve the problem. Suppose someone joins the room after the user is opped and before the user is deopped. 1999, Cory McWilliams, “IRC Oddities”, in alt.irc (Usenet)

Etymology 2

noun

1. (Internet slang) Alternative letter-case form of OP (“original post, original poster”).

Etymology 3

noun

1. (slang, among criminal gangs) Alternative form of opp (“opponent; opposition”).

Etymology 4

From op shop.

verb

1. (Australia, informal, transitive) To buy (something) from an op shop.
2. (Australia, informal, intransitive) To shop at op shops.