Entry 1 sense Webster, 1913 malnutrition /mălˌ-no͞ot-rĭsh'-ən/ · mal·nu·tri·tion · IPA /ˌmæl.nuˈtɹɪʃ.ən/ 01 n. Faulty or imperfect nutrition; inadequate or unbalanced food intake. 1. Faulty or imperfect nutrition; inadequate or unbalanced food intake.(Physiol.)