apprehend in WordNet English dictionary

1. get the meaning of something
   "Do you comprehend the meaning of this letter?"
   grok  get the picture  comprehend  savvy  dig  grasp  compass  apprehend 
   
2. take into custody
   "the police nabbed the suspected criminals"
   collar  nail  apprehend  arrest  pick up  nab  cop 
   
3. anticipate with dread or anxiety
   apprehend  quail at