1. (a.) Requiring the strength of Hercules; hence, very great, difficult, or dangerous; as, an Herculean task.

2. (a.) Having extraordinary strength or size; as, Herculean limbs.

Antaean Atlantean Briarean Brobdingnagian Cyclopean Gargantuan Homeric abstruse abysmal arduous astronomic backbreaking brutal burdensome colossal complex critical crushing delicate demanding difficile difficult effortful elephantine enormous epic exacting forced formidable gargantuan giant giantlike gigantic grueling hairy hard hard-earned hard-fought heavy hefty heroic huge immense infinite intricate jawbreaking jumbo killing knotted knotty labored laborious mammoth mean mighty monster monstrous monumental mountainous no picnic not easy onerous operose oppressive painful prodigious profound punishing rigorous rough rugged set with thorns severe spiny steep strained strenuous stupendous thorny ticklish titanic toilsome tough towering tremendous tricky troublesome uphill vast wearisome wicked