armlock

Short definition from Wiktionary

Noun

1. 1
   A wrestling move in which the opponent's arm is held immobile.
2. 2
   Any of several distinct attacks against an opponent’s arm in martial arts.
3. 3
   A fighting hold in which the arm is used to immobilise an opponent.
4. 4
   Power to control or heavily influence something or someone.

Verb

1. 1
   To hold in an armlock.