1. to cramp up; to tighten; to stiffen

2. to be insistent; to persist (in one's opinion); to stick to one's guns

3. to act tough; to bluff; to be defiant; to be unruly

4. to prop up (e.g. with a post); to support

5. to push out (one's legs or arms); to stretch (e.g. an arm against the wall); to press

6. to thrust (one's opponent)