Available Definitions:
1) a. - Capable of apprehending, or quick to do so; apt; discerning.
2) a. - Knowing; conscious; cognizant.
3) a. - Relating to the faculty of apprehension.
4) a. - Anticipative of something unfavorable' fearful of what may be coming; in dread of possible harm; in expectation of evil.
5) a. - Sensible; feeling; perceptive.