unbend

transitive verb unbent or unbended, unbending

1. to release (a bow, etc.) from strain or tension
2. to relax (the mind) from strain or effort
3. to straighten (something bent or crooked)
4. Naut.
   1. to loosen or unfasten (a rope, sail, etc.)
   2. to untie (a rope)

intransitive verb

1. to become straight or less bent
2. to become free from constraint, stiffness, or severity; relax and be less formal, more natural, etc.