1928, from the noun phrase, from good (adj.) + time (n.). Expression to have a good time "enjoy oneself" attested from 1822; earlier have a good time of it (1771). To make good time "go fast" is from 1838. In Middle English, good time was "prosperous time," also "high time" (that something be done).[good-time etymology, good-time origin, 英语词源]