From Hercules (Greek Hēraklēs, 'glory of Hera'), whose twelve impossible labors made his name synonymous with superhuman effort.
Requiring enormous strength or effort; of or resembling the mythological hero Hercules.
From Latin 'Herculēs' (the Roman name for the Greek hero 'Hēraklēs') + the English adjective suffix '-an.' The Greek name 'Hēraklēs' is composed of 'Hḗrā' (the goddess Hera) + 'kléos' (glory, fame), meaning 'glory of Hera' — deeply ironic, since Hera was his implacable enemy who drove him to the madness that led to the Twelve Labors. Greek 'kléos' comes from PIE *ḱlewos (fame, glory, that which is heard), from the root *ḱlew- (to hear), which also produced Sanskrit