freewill

discretionary, elective, optional

impulsive, instinctive, spontaneous, unpremeditated

conscious, deliberate, intentional, knowing, willful (or wilful)

election, preference, selection

bent, devices, disposition, inclination, leaning, partiality, penchant, predilection, predisposition, proclivity, propensity, tendency

alternative, discretion, option, pick, way