Challenging (7)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">challenging</span>' is the definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for defiant that I've seen before include "Openly resistant" , "Unyielding" , "showing teeth!" , "Uncooperative" , "Boldly resistant -- fainted (anag)" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">challenging</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for formidable that I've seen before include "Intimidating" , "Threatening, challenging" , "Intimidatory" , "Awesome" .)