CategoryDistinguishing basisPractice and omissionFardDefinitive proofPerformance and assent requiredWajibSound non-definitive proofPerformance required; same categorical assent not requiredSunnahApproved established religious wayUpholding expected; blame may apply to unjustified neglectNaflDevotion beyond obligationsReward for performance; no punishment for omission
These are distinct legal classifications, not four interchangeable names for one act. Evidence and consequences determine the category. Fard prayer, witr, emphasized Sunnah, and pure nafl should not be treated as having identical normative status.