1.  mental(a = adj.all) - involving the mind or an intellectual process; "mental images of happy times"; "mental calculations"; "in a terrible mental state"; "mental suffering"; "free from mental defects"
Antonym: physical
Derived forms noun mentality₂, noun mentality₁

2.  mental(a = adj.pert) - of or relating to the mind; "mental powers"; "mental development"; "mental hygiene"
Derived forms noun mentality₂, noun mentality₁

3.  mental(a = adj.pert) - of or relating to the chin- or liplike structure in insects and certain mollusks;

4.  mental(a = adj.pert) genial - of or relating to the chin or median part of the lower jaw;

5.  mental(s = adj.all) - affected by a disorder of the mind; "a mental patient"; "mental illness"

   Of or pertaining to the chin; genian; as, the mental nerve; the mental region. [1913 Webster]

   A plate or scale covering the mentum or chin of a fish or reptile. [1913 Webster]

   Of or pertaining to the mind; intellectual; as, mental faculties; mental operations, conditions, or exercise. [1913 Webster]
"What a mental power
This eye shoots forth!" [1913 Webster]

mental, adj. & n.
--adj.
1 of or in the mind.
2 done by the mind.
3 colloq. a insane. b crazy, wild, eccentric (is mental about pop music).
--n. colloq. a mental patient.

Idiom:
mental age the degree of a person's mental development expressed as an age at which the same degree is attained by an average person. mental arithmetic arithmetic performed in the mind. mental asylum (or home or hospital or institution) an establishment for the care of mental patients. mental cruelty the infliction of suffering on another's mind, esp. Law as grounds for divorce. mental defective esp. US a person with impaired mental abilities. mental deficiency imperfect mental development leading to abnormally low intelligence. mental illness a disorder of the mind. mental nurse a nurse dealing with mentally ill patients. mental patient a sufferer from mental illness. mental reservation a qualification tacitly added in making a statement etc.

Derivative:
mentally adv.

Etymology:
ME f. OF mental or LL mentalis f. L mens -ntis mind

N  intellect, mind, understanding, reason, thinking principle, rationality, cogitative faculties, cognitive faculties, discursive faculties, reasoning faculties, intellectual faculties, faculties, senses, consciousness, observation, percipience, intelligence, intellection, intuition, association of ideas, instinct, conception, judgment, wits, parts, capacity, intellectuality, genius, brains, cognitive powers, intellectual powers, wit, ability, wisdom, Vernunft, Verstand, soul, spirit, ghost, inner man, heart, breast, bosom, penetralia mentis, divina particula aurae, heart's core, the Absolute, psyche, subliminal consciousness, supreme principle, brain, organ of thought, seat of thought, sensorium, sensory, head, headpiece, pate, noddle, noggin, skull, scull, pericranium, cerebrum, cranium, brainpan, sconce, upper story, central processing unit, CPU, arithmetic and logical unit, ALU, metaphysics, psychics, psychology, ideology, mental philosophy, moral philosophy, philosophy of the mind, pneumatology, phrenology, craniology, cranioscopy, ideality, idealism, transcendentalism, spiritualism, immateriality, universal concept, universal conception, metaphysician, psychologist, intellectual, mental, rational, subjective, metaphysical, nooscopic, spiritual, ghostly, psychical, psychological, cerebral, animastic, brainy, hyperphysical, superphysical, subconscious, subliminal, immaterial, endowed with reason, in petto, ens rationis, frons est animi janua, locos y ninos dicen la verdad, mens sola loco non exulat, my mind is my kingdom, stern men with empires in their brains, the mind, the music breathing from her face, thou living ray of intellectual Fire.

create by mental act, creating by mental acts, mental ability, mental abnormality, mental age, mental anguish, mental attitude, mental balance, mental block, mental capacity, mental case, mental confusion, mental defectiveness, mental deficiency, 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