/ Thesaurus / F Synonyms of four o'clock Find synonyms for: Noun1. four o'clock, flowerusage: any of several plants of the genus Mirabilis having flowers that open in late afternoonWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language