Large African snake (5)
I believe the answer is:
mamba
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">large 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 "Venomous snake; rhymes with dance" , "Venomous Afr. snake" , "Large African snake" , "serpent" , "Snake that might kill" .)