Become less tense (5)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">become less tense</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for relax that I've seen before include "Unbend" , "Put your feet up" , "Make (rule) less strict" , "Take one's ease" , "Hang loose" .)
(Other definitions for loosen up that I've seen before include "Relax - don't be so tense" , "Become less shy; warm up for an activity" , "Let your hair down" , "Become mentally relaxed" , "Prepare for activity; become less shy" .)