mental deficiency(n = noun.cognition) moronity - mild mental retardation;
is a kind of backwardness, mental retardation, retardation, slowness, subnormality

acquired immune deficiency syndrome, color vision deficiency, colour vision deficiency, create by mental act, creating by mental acts, deficiency, deficiency disease, iron deficiency anaemia, iron deficiency anemia, lactase deficiency, mass deficiency, mental, mental ability, mental abnormality, mental age, mental anguish, mental attitude, mental balance, mental block, mental capacity, mental case, mental confusion, mental defectiveness, mental dexterity, mental disease, mental disorder, mental disturbance, mental energy, mental exhaustion, mental faculty, mental health, mental home, mental hospital, mental hygiene, mental illness, mental image, mental imagery, mental institution, mental lexicon, mental measurement, mental note, mental object, mental picture, mental process, mental quickness, mental rejection, mental representation, mental reservation, mental retardation, mental soundness, mental state, mental strain, mental synthesis, mental telepathist, mental test, mental testing, mental unsoundness, mineral deficiency, vitamin deficiency, zinc deficiency