›If you or your muscles tense, your muscles become stiff and tight because you are frightened or nervous, or are preparing yourself to do something: Don't tense your shoulders, just relax.I could feel myself tense up as he touched my neck.Tight and tighteningtensed up›very nervous and worried and unable to relax because of something that is going to happen: You seem very tensed up. Are you still waiting for that call?Anxious and worried