Left newt out (4)
I believe the answer is:
went
'left' is the definition.
(I've seen this before)
'newt out' is the wordplay.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'newt' anagrammed gives 'WENT'.
(Other definitions for went that I've seen before include "Departed (not hand)" , "Proceeded; departed" , "Travelled" , "Left; disappeared" , "Changed location" .)