Uncertain, doubtful (4)
I believe the answer is:
iffy
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">uncertain</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(both can mean dubious)</span><br/ ><br/ >'<span class="explanation-format__original">doubtful</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for iffy that I've seen before include "Doubtful, not definite" , "Informally dubious or uncertain" , "Dodgy" , "Uncertain (colloq.)" , "Questionable - uncertain" .)