Futile, vain, fruitless, bootless, abortive all denote barren of result.
Furnish, equip, outfit, appoint, accouter, arm are comparable when they mean to supply a person or something used by him with the adjuncts necessary or appropriate to his daily living or his occupation.
Function, office, duty, province are comparable when they mean the act, acts, activities, or operations expected of a person or thing by virtue of his or its nature, structure, status, or position.
Fun, jest, sport, game, play are comparable when they denote something (as an activity, an utterance, or a form of expression) that provides diversion or amusement or is intended to arouse laughter.
Frustrate, thwart, foil, baffle, balk, circumvent, outwit mean either to defeat a person attempting or hoping to achieve an end or satisfy a desire or, in some cases, to defeat another’s desire.
Friendship, amity, comity, goodwill are comparable when they denote the relation (or, in the first three instances, the alliance) existing between persons, communities, states, or peoples that are in accord and in sympathy with each other.