unbend in WordNet English dictionary

1. become less tense, rest, or take one's ease
   "He relaxed in the hot tub"; "Let's all relax after a hard day's work"
   relax  loosen up  unbend  unwind  decompress  slow down 
   
2. make less taut
   "relax the tension on the rope"
   relax  unbend 
   
3. straighten up or out; make straight
   straighten  unbend 
   
4. release from mental strain, tension, or formality
   "unbend the mind from absorbing too much information"
   unbend 
   
5. free from flexure
   "unbend a bow"
   unbend 
   
6. unfasten, as a sail, from a spar or a stay
   unbend