act vs activity

Other hyponyms of act include action, acquiring, getting, causation, causing, delivery, obstetrical delivery, departure, going, going away, leaving, discovery, find, uncovering, disposal, disposition, effectuation, implementation, egress, egression, emergence, equalisation, equalization, leveling, digging up, disinterment, exhumation, mitsvah, mitzvah, actuation, propulsion, recovery, retrieval, running away, touch, touching, nonaccomplishment, nonachievement, leaning, motivating, motivation, assumption, rejection, forfeit, forfeiture, sacrifice, derivation, hire, wear, wearing, assessment, judgement, judgment, production, stay, abidance, residence, residency, inactivity, hinderance, hindrance, interference, stop, stoppage, distribution, legitimation, permissive waste, waste, proclamation, promulgation, communicating, communication, speech act, subtweeting, shout-out.