Cosmic cloud (6)
I believe the answer is:
nebula
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cosmic cloud</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for nebula that I've seen before include "Diffuse cloud of particles and gas in space" , "A little cloudy" , "Gas/dust cloud in space" , "Unable (anag)" , "Mass of interstellar gas" .)