cudgel

Short definition from Wiktionary

Noun

1. 1
   A short heavy club with a rounded head used as a weapon.
2. 2
   Anything that can be used as a threat to force one's will on another.

Verb

1. 1
   To strike with a cudgel.
2. 2
   To exercise (one's wits or brains) in an effort to force a memory or solution; to rack (one's mind).