1.spasm
N-VAR A spasm is a sudden tightening of your muscles, which you cannot control.
2.knack
N-COUNT A knack is a particularly clever or skilful way of doing something successfully, especially something which most people find difficult.
3.twinge
N-COUNT A twinge is a sudden sharp pain.
4.knead
V-T If you knead a part of someone's body, you press or squeeze it with your fingers.
