/ Thesaurus / C Synonyms of cotter pin Find synonyms for: Noun1. cotter pin, cotter, cottarusage: a cotter consisting of a split pin that is secured (after passing through a hole) by splitting the ends apartWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: foliage Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language