Wayward (10)
(Other definitions for headstrong that I've seen before include "Obstinately rash" , "pig-headed" , "strong-willed" , "Stubborn" , "Obstinate" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">wayward</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 errant that I've seen before include "Sinful" , "Like many a knight" , "Behaving badly" , "like Don Quixote?" , "Wayward - ranter (anag)" .)