Entry 1 sense Webster, 1913 Abirritation · Ab·ir·ri·ta·tion · IPA /ˌæb.ɪɹ.ɪˈteɪ.ʃn̩/ 01 n. A pathological condition opposite to that of irritation; debility; lack of strength; asthenia. 1. A pathological condition opposite to that of irritation; debility; lack of strength; asthenia.(Med.)