Semiaquatic salamander (4)
I believe the answer is:
newt
'semiaquatic salamander' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for newt that I've seen before include "Small often colourful salamander of the Northern Hemisphere" , "Went to find amphibian" , "Amphibian such as the salamander" , "Garden-pond amphibian" , "legless for a start" .)