more slippery, in a way (5)
I believe the answer is:
icier
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">more slippery in a way</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 icier that I've seen before include "with increased chance of freezing" , "More glacial" , "Colder even than 31 Across" , "More slippery" , "More treacherous" .)