【Mental】 , 【intellectual】 , 【psychic】 , 【intelligent】 , 【cerebral】 can mean of, relating to, or characteristic of that sum total of powers or functions called variously mind, intellect, soul, psyche, or brain (compare MIND 2 ).
In general 【mental】 applies directly to what has to do with the mind as a real or as a purely theoretical entity.
【Intellectual】 differs from 【mental】 not only in its reference to the intellect, and therefore to such higher powers of the mind as the comprehension of the abstract or difficult and the ability to reason, but also because it is directly applicable to persons, their utterances, acts, and qualities. It often carries an implied contrast to emotional and suggests an attachment to study and reflection.
【Psychic】 implies a relation to the inner self or psyche and guides the attention away from notions of the physical, physiological, or organic.
【Intelligent】 (see also 【INTELLIGENT】 2 ) implies such a degree of 【mental】 power in a person or animal as to make possible appraisal of a situation and formulation of sound or reasonable decisions; it is often contrasted with stupid or silly.
【Cerebral】 basically calls to mind the higher centers of the brain and may suggest 【intellectual】 activity or inclination especially as being coolly analytical and withdrawn from the sensuous and emotional aspects of the 【mental】 life.