unstrain

From un- +‎ strain.

unstrain (third-person singular simple present unstrains, present participle unstraining, simple past and past participle unstrained)

1. (transitive) To relieve from strain; to relax.
   • 1611, Ben Jonson, Love Freed from Ignorance and Folly:

     Then, to prison of the night
     Did condemn those sisters bright,
     There for ever to remain,
     'Less they could the knot unstrain

• “unstrain”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.

• insurant, untrains