Godless, a. — Webster enters it under “godless”
Having, or acknowledging, no God; without reverence for God; impious; wicked. -- God"less*ly, adv. -- God"less*ness, n.
Shades of meaning
Fernald lists godlessness only as an antonym, under religion.
He lists it without comment; the entries above explain its neighbors.
Synonyms
none given