Flourishing (10)
(Other definitions for successful that I've seen before include "achieving aim" , "Prosperous" , "Winning; flourishing" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">flourishing</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Another definition for burgeoning that I've seen is " In a state of growth".)