1. op - Noun
2. op - Adjective
3. op - Verb
4. Op - Proper noun
(informal) Clipping of operation.
My mother's going in for her knee op today.
(informal) Clipping of operator.
(informal) An amateur radio operator.
(Internet) An operator on IRC, who can moderate the chat channel, ban users, etc.
(Internet slang, chiefly in the plural) Clipping of opinion.
Ops on my new drawing?
(chiefly attributive) Ellipsis of op art.
an op painting; op artworks
op (third-person singular simple present ops, present participle opping, simple past and past participle opped)
(transitive, Internet) To promote (an IRC user) to an operator.
Antonym: deop
op
(Internet slang) Alternative letter-case form of OP (“original post, original poster”).
op (plural ops)
(slang, among criminal gangs) Alternative form of opp (“opponent; opposition”).
(Australia, informal, transitive) To buy (something) from an op shop.
(Australia, informal, intransitive) To shop at op shops.
Initialism of Overall Position.
(theater) Initialism of opposite prompt; stage right.
(Internet) Initialism of original poster; the person who started a thread.
I don't think your response really answers the OP's question.
(Internet) Initialism of original post.
(military, law enforcement) Initialism of observation post.
(organic chemistry) Abbreviation of organophosphate.
(slang) Initialism of other person's; a cigarette cadged from someone.
(publishing) Abbreviation of out of print.
Abbreviation of overproof.
(video games) Abbreviation of overpowered.
(Internet, music) Initialism of overplayed.
OP
(religious) Initialism of Ordo Praedicatorum (Order of Preachers, the Dominicans, a religious order).
Initialism of opening credits.
Initialism of opening theme.
Source: en.wiktionary.org