Slime (3)
I believe the answer is:
goo
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">slime</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for goo that I've seen before include "syrup" , "Sticky wet material or sickly sentiment" , "Sentimentality (sl.)" , "Sticky and slimy stuff" , "Sticky substance (colloq.)" .)