From WordNet (r) 3.0 (2006) [wn]:
intense
adj 1: possessing or displaying a distinctive feature to a
heightened degree; "intense heat"; "intense anxiety";
"intense desire"; "intense emotion"; "the skunk's intense
acrid odor"; "intense pain"; "enemy fire was intense"
[ant: mild]
2: extremely sharp or intense; "acute pain"; "felt acute
annoyance"; "intense itching and burning" [syn: acute,
intense]
3: (of color) having the highest saturation; "vivid green";
"intense blue" [syn: intense, vivid]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Intense \In*tense"\, a. [L. intensus stretched, tight, p. p. of
intendere to stretch: cf. F. intense. See Intend, and cf.
Intent, and cf. Intent, a.]
[1913 Webster]
1. Strained; tightly drawn; kept on the stretch; strict; very
close or earnest; as, intense study or application;
intense thought.
[1913 Webster]
2. Extreme in degree; excessive; immoderate; as:
(a) Ardent; fervent; as, intense heat.
(b) Keen; biting; as, intense cold.
(c) Vehement; earnest; exceedingly strong; as, intense
passion or hate.
(d) Very severe; violent; as, intense pain or anguish.
(e) Deep; strong; brilliant; as, intense color or light.
[1913 Webster]
In this intense seclusion of the forest.
--Hawthorne.
[1913 Webster]