Give off, as light (4)
I believe the answer is:
emit
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">give off as light</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 emit that I've seen before include "Throw out" , "Send out in time" , "Exude" , "Produce and discharge" , "Let out" .)