Asteroid (5,6)
I believe the answer is:
minor planet
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">asteroid</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for minor planet that I've seen before include "small world!" , "rock from space" , "Old name for asteroid - Pluto?" , "Ceres, say" .)