Begin to melt (4)
I believe the answer is:
thaw
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">begin to melt</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for thaw that I've seen before include "Melt in heat" , "Become friendlier; melt" , "(Of snow or ice) melt" , "Frost going" , "Become liquid" .)