1. requiring or apparently requiring no effort (Freq. 1) - the swallows glided in an effortless way through the busy air • Ant: effortful • Similar to: facile, unforced, unstrained • See Also: easy • Derivationally related forms: effortlessness 2. not showing effort or strain - a difficult feat performed with casual mastery - careless grace • Syn: casual • Similar to: easy • Derivationally related forms: effortlessness, casualness (for: casual)