Apprehensive

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

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.