Answer: unclench

AnswerCrossword Clue
UNCLENCHLoosen, as one's butt
UNCLENCHRelax, as one's fist
UNCLENCHRelax
UNCLENCHOpen, as a fist
unclenchto open from a clenched position, also UNCLINCH
unclenchRelax from a clenched state
unclenchRelease (a clenched part of the body)