compulsion  
noun uk/kəmˈpʌl.ʃən/ us/kəmˈpʌl.ʃən/
  (WANT)      
  [ C ]强烈冲动;强烈欲望,难以抗拒的欲望 
a very strong feeling of wanting to do something repeatedly that is difficult to control
  For many people, dieting is a compulsion. 许多人都有节食的冲动。 
 [ + to infinitive ] I seem to have a constant compulsion to eat. 我好像总有想吃东西的欲望。 
   (FORCE)      
 [ S or U ]强迫力,强制力 
a force that makes you do something
  He seems to be driven by some kind of inner compulsion. 他似乎受到某种内在力量的驱使。 
 [ + to infinitive ] We were under no compulsion to attend. 我们并不是非要去参加不可。 
 Don't feel under any compulsion to take me with you. 你不必非要勉强带我跟你一起去。 
 See also: compel