Oleaginous, unctuous (4)
I believe the answer is:
oily
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">oleaginous</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >'<span class="explanation-format__original">unctuous</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that unctuous can be written as oily)</span><br/ ><br/ ></span>
(Other definitions for oily that I've seen before include "Like a lot of fish" , "Unctuous" , "Smarmy" , "Unpleasantly ingratiating" , "Greasy - obsequious" .)