intense

Of a characteristic: extreme or very high or strong in degree; severe; also, excessive, towering.

Nor was I yet able to passe through any of the narrower streets, but kept the widest; the ground and air, smoake and fiery vapour, continu'd so intense that my haire was almost sing'd, and my feete unsufferably surbated.

[…] Nature had a robe of glory on, / And the bright air o'er every shape did weave / Intenser hues, so that the herbless stone, / The leafless bough among the leaves alone, / Had being clearer than its own could be, […]

Of a thing: possessing some characteristic to an extreme or very high or strong degree.

[T]h' intense atom glows / A moment, then is quenched in a most cold repose.

These pendent lamps and chandeliers are bright / As earthly fires from dull dross can be cleansed; / Yet could my eyes drink up intenser beams / Undazzled—this is darkness—when I close / These lids, i see far fiercer brilliances,— […]

Of feelings, thoughts, etc.: strongly focused; ardent, deep, earnest, passionate.

intense study

intense thought

Of a person: very emotional or passionate.

The artist was a small, intense man with piercing blue eyes.

Fair Æsthetic (suddenly, and in deepest tones, to Smith, who has just been introduced to take her in to Dinner). "Are you Intense?"

Under tension; tightly drawn; strained, stressed, tense.