Noah Webster's New International Dictionary of the English Language

1. (superl.) Easily frightened; timid; as, a shy bird.

2. (superl.) Reserved; coy; disinclined to familiar approach.

3. (superl.) Cautious; wary; suspicious.

4. (v.) To start suddenly aside through fright or suspicion; -- said especially of horses.

5. (v. t.) To throw sidewise with a jerk; to fling; as, to shy a stone; to shy a slipper.

6. (n.) A sudden start aside, as by a horse.

7. (n.) A side throw; a throw; a fling.