Hooded serpent (5)
I believe the answer is:
cobra
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">hooded serpent</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for cobra that I've seen before include "hamadryad" , "Reptile (found in Cabinet Office Briefing Room A?)" , "Sinuous creature" , "Poisoner" , "Something with a hood" .)