n.

1. （被）強迫，（被）強制[U][+to-v]
   John will take his medicine only by compulsion.

   只有對他用強制手段約翰才會服藥。

2. 強制力，強迫力[U]
3. 【心】強迫作用（一種難以抵制的衝動）[C][+to-v]
   She felt a sudden compulsion to hit him.

   她突然感到一種難以抗拒的衝動，想要揍他。

n.

1. the action of compelling or the state of being compelled; constraint.
2. an irresistible urge to behave in a certain way.