The Greek noun apheidia comes from the negative particle a- and pheidesthai (to spare), meaning "not sparing" — thus harsh treatment, severity, or rigorous self-denial. It appears only once in the New Testament (Colossians 2:23), where Paul describes certain ascetic practices as having "an appearance of wisdom" but ultimately being of "no value in restraining sensual indulgence."
Paul's use of apheidia is a critique of a common religious error: the belief that extreme self-denial earns spiritual merit or overcomes sin. The Colossian errorists imposed elaborate food regulations, self-abasement, and asceticism. Paul's answer: these things look wise but they don't address the heart. True transformation comes not from harsh treatment of the body but from "setting your hearts on things above" (Colossians 3:1). Grace, not severity, produces genuine holiness.