/ Thesaurus / X Synonyms of xyy Find synonyms for: Noun1. XYY, sex chromosomeusage: (genetics) abnormal complement of sex hormones in a male who has two Y chromosomesWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: pristine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language