unbend

Short definition from Wiktionary

Verb

1. 1
   To remove a bend so as to make, or allow to become, straight.
2. 2
   To release (a load) from a strain or from exertion; to set at ease for a time; to relax.
3. 3
   To unfasten sails from the spars or stays to which are attached for use.
4. 4
   To cast loose or untie
5. 5
   To cease to be bent; to become straight.
6. 6
   To relax in exertion, attention, severity, or the like
7. 7
   to enjoy oneself; to become affable and free from formality