<p><strong>Adjective</strong></p><ul><li>burdensome, oppressive, or troublesome; causing hardship: onerous duties.</li><li>having or involving obligations or responsibilities, especially legal ones, that outweigh the advantages: an onerous agreement.</li></ul><p><strong>Synonyms</strong></p><ul><li>galling</li><li>irksome</li><li>grievous</li><li>heavy</li></ul>