Deadly African snake (5)
I believe the answer is:
mamba
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">deadly african snake</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 mamba that I've seen before include "Death-dealing African" , "Deadly creature" , "Poisonous creature" , "one venomous" , "Venomous African snake (often black)" .)