One who affects; a person who influences, or one who pretends or feigns.
From 'affect' (Latin 'afficere'—to influence, move) + '-er' (one who does). The '-er' suffix creates agent nouns from verbs, marking someone who performs the action.
An 'affecter' is anyone who influences or affects others—but it can also mean someone who 'affects' or fakes emotions. The word cleverly works both ways, like the verb 'affect' itself!
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