Emit light, shine (4)
I believe the answer is:
glow
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">emit light</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(glowing is a kind of emiting light)</span><br/ ><br/ >'<span class="explanation-format__original">shine</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for glow that I've seen before include "Brightness" , "Radiate or redden" , "Shine, maybe in dark" , "Emanate light" , "Give out light without flames" .)