untense

Adjective

 * 1) Not tense.

Verb

 * 1)  To (cause to) be no longer tense; to relax or loosen.
 * 2) * 1977-1980, Lou Sullivan, personal diary, quoted in 2019, Ellis Martin, Zach Ozma (editors), We Both Laughed In Pleasure
 * It's incredible the wave of relaxation that has swept over me in the past few hours. Walking down the street, I didn't even have to concentrate on untensing in my facial muscles (which I realize are so often twisted up).