Once meant 'to stupefy' in Old French — the journey from 'stare stupidly' to 'entertain' took three centuries.
To entertain or cause laughter; to hold someone's attention in a pleasant way.
From Old French "amuser" ("to divert, to cause to stare stupidly, to stupefy"), a compound of "a-" (from Latin "ad-," "toward") and "muser" ("to stare, to ponder, to idle, to gaze vacantly"). The origin of "muser" is debated: it may derive from Medieval Latin "mūsum" ("muzzle, snout"), from Proto-Germanic *mūsą, referring to an animal standing with its nose in the air — hence "to stand gaping." Alternatively, some connect "muser" to Old French "mus" ("hiding place"), suggesting the original sense was "to hide, to be concealed
In its original English sense, 'amuse' meant to stupefy or distract — military commanders would 'amuse' an enemy by feinting in one direction while attacking in another. The shift from 'to bewilder' to 'to entertain' took about two centuries, completing by the 1700s.