Noah Webster's Dictionary 1. (v. t.) To make worse; to diminish in quantity, value, excellence, or strength; to deteriorate; as, to impair vision, character, the mind, value. 2. (v. t.) To grow worse; to deteriorate. 3. (a.) Not fit or appropriate. 4. (n.) Diminution; injury.

Multi-Version Concordance Impair (1 Occurrence) Ruth 4:6 The near kinsman said, "I can't redeem it for myself, lest I mar my own inheritance. Take my right of redemption for yourself; for I can't redeem it." (See RSV)