/ Thesaurus / P Synonyms of phase i Find synonyms for: Noun1. phase I clinical trial, phase I, clinical trial, clinical testusage: a clinical trial on a few persons to determine the safety of a new drug or invasive medical device; for drugs, dosage or toxicity limits should be obtainedWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language