1. spoil, ruin, break, mar. Injure, impair mean to harm or damage something. Injure is a general term referring to any kind or degree of damage: to injure one's spine; to injure one's reputation. To impair is to make imperfect in any way, often with a suggestion of progressive deterioration and of permanency in the result: One's health is impaired by overwork. 2. maltreat, abuse.