Destructive (7)
I believe the answer is:
ruinous
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">destructive</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ruinous that I've seen before include "Calamitous, crippling" , "Exorbitant" , "Destructive; dilapidated" , "Causing destruction" , "ikely to cause harm" .)