mental

adj

1. (relational)Of or relating to the mind or specifically the total emotional and intellectual response of an individual to external reality.

   “I don't mean all of your friends—only a small proportion—which, however, connects your circle with that deadly, idle, brainless bunch—the insolent chatterers at the opera,[…], the neurotic victims of mental cirrhosis, the jewelled animals whose moral code is the code of the barnyard—!”

2. (relational)Of or relating to the mind or specifically the total emotional and intellectual response of an individual to external reality.

   “mental science”

3. (relational)Of or relating to the mind or specifically the total emotional and intellectual response of an individual to external reality.

   “mental acuity”

4. (relational)Of or relating to the mind or specifically the total emotional and intellectual response of an individual to external reality.

   “Irregular bedtimes may disrupt healthy brain development in young children, according to a study of intelligence and sleeping habits. ¶ Going to bed at a different time each night affected girls more than boys, but both fared worse on mental tasks than children who had a set bedtime, researchers found.”

5. (relational)Of or relating to the mind or specifically the total emotional and intellectual response of an individual to external reality.

   “the distinction between physical things and mental ideas”

6. Of, relating to, or affected by a psychiatric disorder.

   “a mental patient”

7. (relational)Of, relating to, or affected by a psychiatric disorder.

   “mental hospitals”

8. (Australia, Canada, Ireland, New-Zealand, UK, colloquial, comparable, dated)Of, relating to, or affected by a psychiatric disorder.

   “He is the most mental freshman I've seen yet.”

   “He went mental on us.”

9. (Australia, Ireland, New-Zealand, UK, colloquial, comparable)Enjoyable or fun, especially in a frenetic way.

   “That was a mental party last night.”

10. Of or relating to telepathic or mind-reading powers.

    “mental telepathy”

11. (not-comparable, relational)Of or relating to the chin or median part of the lower jaw, genial.

    “the mental nerve, the mental region”

12. (not-comparable, relational)Of or relating to the chinlike or liplike structure.

noun

1. (slang)State of mind; ellipsis of mental state.

   “y'all need to fix your mentals”

2. (India, offensive)A mentally challenged person.
3. A plate or scale covering the mentum or chin of a fish or reptile.