Mousy (5)
I believe the answer is:
timid
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mousy</span>' is the definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for timid that I've seen before include "Lacking self-confidence" , "doormat" , "Easily alarmed, shy" , "Diffident, faint-hearted" , "Lacking in courage" .)