'em /əm/pronoun 1phrases 2 pronoun1 •(informal) a short form of "them", used in quick speech after a verb or a prepositionSome are become great, some atcheeues greatnesse, and some haue greatnesse thrust vppon em. — 1601 Phrases with 'em shoot 'em upA piece of media which depicts considerable gunplay. up and at 'emVigorously launched or launching into an activity.