infirm
Cross references: 1. weak in.firm \in-'f*rm\ aj [ME, fr. L infirmus, fr. in- + firmus firm] 1: of poor or deteriorated vitality; esp : feeble from age 2: weak of mind, will, or character : IRRESOLUTE, VACILLATINGM 3: not solid or stable : INSECURE - in.firm.ly av