Home › Words › E › eptitudeeptitude/ɛp.tɪ.t(j)ud/eptitude means effectiveness or proficiency in (something), especially contrasting natural ability or aptitude.eptitude is pronounced /ɛp.tɪ.t(j)ud/.EtymologyBack-formation from ineptitude. By surface analysis, ept + -itude.nounEffectiveness or proficiency in (something), especially contrasting natural ability or aptitude.Definitions & examples from Wiktionary (CC BY-SA 3.0).