leaning

curve, downside, shift, swing, turn, turnabout, upside

custom, habit, propensity, tenor, way

countercurrent, countertrend

undercurrent, undertow

favor, one-sidedness, partisanship, prejudice

endowment, faculty, flair, genius, gift, knack, talent

addiction, appetite, fancy, fondness, like, liking, preference, taste

forte, speciality, specialty

convention, custom, habit, pattern, practice (also practise), routine, trick, way, wont

eccentricity, idiosyncrasy, kink, oddity, peculiarity, quirk, singularity