Cold-blooded vertebrate (7)
I believe the answer is:
reptile
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cold-blooded vertebrate</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for reptile that I've seen before include "Serpent" , "Malignant creature" , "Snake or crocodile, say" , "Eg, snake, lizard, etc" , "eg Crocodile" .)