/ Dictionary / Index O onerous: Meaning and Definition of Find definitions for: on•er•ous Pronunciation: (on'ur-us, ō'nur-), [key] — adj. burdensome, oppressive, or troublesome; causing hardship: onerous duties. having or involving obligations or responsibilities, esp. legal ones, that outweigh the advantages: an onerous agreement. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: onerous (Thesaurus) one-reeler oneself Related Content Daily Word Quiz: grimace Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language