1. (n.) A natural or acquired disposition or capacity for a particular purpose, or tendency to a particular action or effect; as, oil has an aptitude to burn.

2. (n.) A general fitness or suitableness; adaptation.

3. (n.) Readiness in learning; docility; aptness.

a thing for ability acuity acuteness admissibility adroitness affinity an ear for an eye for animus applicability appositeness appropriateness aptness bent bias braininess brightness brilliance capability capacity capacity for cast chance character clear thinking cleverness conatus conduciveness constitution contingency delight dexterity diathesis disposition docility eagerness eccentricity educability esprit eventuality expectation facility faculty fair expectation favorable prospect feeling for felicity fitness fittedness flair genius genius for gift gift for giftedness gifts good chance grain idiosyncrasy impressionability inclination individualism innate aptitude intellect intelligence keen-wittedness keenness kidney leaning liability liableness likelihood likeliness liking make makeup malleability mental alertness mental set mercurial mind mettle mind mind-set mold moldability motivation native cleverness nature nimble mind nimble-wittedness nimbleness nous obligation odds outlook penchant plasticity pliability possibility predilection predisposition preference prejudice presumption presumptive evidence probabilism probability proclivity proneness propensity propriety prospect qualification quick parts quick thinking quick wit quick-wittedness quickness readiness ready wit reasonable ground reasonable hope receptivity relevance savvy sensitivity to set sharp-wittedness sharpness slant smartness smarts soft spot sprightly wit stamp strain streak stripe suitability suitableness susceptibility talent teachability teachableness temper temperament tendency trainableness tropism turn turn for turn of mind twist type verisimilitude warp weakness well-grounded hope willingness