One who lights up (6)
I believe the answer is:
smoker
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">one who lights up</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 smoker that I've seen before include "Addict perhaps" , "parrot!" , "Regular cigarette user" , "Puffer" , "one cures" .)