A Go-Go

Antonyms for a go-go:

out, past, dull, unfashionable, poor, old, outdated, antiquated, worn, old-fashioned, unpopular, unstylish.

Synonyms for a go-go:

fashionable (adjective)

chic, chichi, contemporary, current, customary, dashing, faddy, favored, fly, genteel, hot, in style, in vogue, last word, latest, mod, modern, modish, natty, new, newfangled, now, popular, prevailing, rakish, smart, swank, trendsetting, trendy, up-to-the-minute, upscale, usual, well-liked, all the rage, in-thing, à la mode, latest thing, with it.

in (adjective)

posh, stylish, swanky, trig, up to the minute.