to research, to study

a target, a mark, a bullseye / an objective, an object (of doing something)

as far as ... is concerned; in terms of ...

everything

(colloquial) current boyfriend

(slang) Alternative form of 彼氏 (kareshi, “boyfriend”)

everyone, one and all

historian

study of history

(Internet slang, especially anime and manga fandom) events or things from the past which one wants to whitewash/erase from history (due to it being embarrassing, poorly received, etc.); dark past