Strict vegetarian (5)
I believe the answer is:
vegan
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">strict vegetarian</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 vegan that I've seen before include "Person refraining from using animal products in any way" , "One not eating animals" , "An extreme vegetarian" , "Avoiding animal products" , "one not using animals" .)