<p><strong>Adjective</strong></p><ul><li>requiring the great strength of a Hercules</li><li>very hard to perform</li><li>formidable</li><li>onerous</li><li>arduous</li><li>prodigious</li><li>having enormous strength, courage, or size</li><li>of or relating to Hercules or his labors</li></ul>