Fizzless (4)
I believe the answer is:
flat
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fizzless</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for flat that I've seen before include "with no relief" , "Digs perhaps" , "Quarters - punctured - smooth" , "Featureless" , "Level; dull" .)