/ Thesaurus / I Synonyms of illegitimately Find synonyms for: Adverb1. illegitimately, illicitlyusage: in a manner disapproved or not allowed by custom; "He acted illegitimately when he increased the rent fourfold"2. illegitimately, out of wedlockusage: of biological parents not married to each other; "this child was born illegitimately"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: penury Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language