/ Thesaurus / P Synonyms of principal investigator Find synonyms for: Noun1. principal investigator, PI, scientistusage: the scientist in charge of an experiment or research projectWordNet 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