Noah Webster's New International Dictionary of the English Language

1. (v. t.) To twitch; to pull; to tweak.

2. (v. t.) To understand the meaning of; to comprehend; as, do you twig me?

3. (v. t.) To observe slyly; also, to perceive; to discover.

4. (n.) A small shoot or branch of a tree or other plant, of no definite length or size.

5. (v. t.) To beat with twigs.