Etymology
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intellect (n.)
"the sum of the cognitive facilities (except sense or sense and imagination), the capacity for reasoning truth," late 14c. (but little used before 16c.), from Old French intellect "intellectual capacity" (13c.), and directly from Latin intellectus "discernment, a perception, understanding," noun use of past participle of intelligere "to understand, discern" (see intelligence). The Latin word was used to translate Greek nous "mind, thought, intellect" in Aristotle.
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intellectual (adj.)
late 14c., "grasped by the understanding" (rather than by the senses), from Old French intellectuel (13c.) and directly from Latin intellectualis "relating to the understanding," from intellectus "discernment, understanding," noun use of past participle of intelligere "to understand, discern" (see intelligence).

Sense of "characterized by a high degree of intellect" is from 1819. Meaning "appealing to or engaging the mental powers" is from 1834. Intellectual property "products of the intellect" is attested from 1845. Adjective formations in the sense "of or pertaining to the intellect" included intellective (early 15c.), intellectile (1670s).
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intellectualize (v.)
1819 (Coleridge), "infuse with intellectual quality," from intellectual + -ize. From 1827 as "exercise the mind, reason upon a matter of intellect." Related: Intellectualized; intellectualizing.
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intellectuality (n.)
mid-15c., "the part of the mind which understands; understanding, intellect;" from Old French intellectualité and directly from Late Latin intellectualitas, from Latin intellectualis "relating to the understanding" (see intellectual).
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intellectualism (n.)
1818, in philosophy, "belief in the supremacy of the intellect," probably based on German Intellektualismus (said by Klein to have been coined 1803 by Friedrich Wilhelm Joseph von Schelling (1775-1854) from Late Latin intellectualis); see intellectual + -ism. Meaning "devotion to intellectuality" also is from 1818.
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intellectual (n.)
1590s, "mind, intellect, intellectual powers," from intellectual (adj.). The meaning "an intellectual person" is attested from 1650s but was hardly used in that sense in 19c. and the modern use in this sense seems to be a re-coinage from c. 1906. Related: Intellectuals.
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derangement (n.)

1737, "disturbance of regular order," from French dérangement (17c.), from déranger (see derange). Mental sense "disturbance of the intellect or reason" is from 1800.

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highbrow (n.)
"person of superior intellect and taste," 1884, from high (adj.) + brow (n.). Compare lowbrow. The adjective also is attested from 1884.
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noesis (n.)

"intellect, intelligence," 1820, from Greek noēsis "intelligence, thought," from noein "to see, perceive, have mental perception," from noos "mind, thought" which is of uncertain origin.

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greenhead (n.)
1580s, "young, untrained intellect," from green (adj.) + head (n.). As a type of biting fly with a green-colored head, by 1837.
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