Tireless (13)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tireless</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for indefatigable that I've seen before include "with no end of energy" , "Assiduous" , "Persisting tirelessly" , "Relentless" , "Unremitting" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tireless</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Another definition for inexhaustible that I've seen is " Tireless".)