Going out of turn, Bert upsets the blighter! (5)
I believe the answer is:
brute
'the blighter' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'going out of turn bert upsets' is the wordplay.
I cannot really see how this works, but
'turn' could be 'u' (a 'U-turn' is a kind of turn) and 'u' is present in the answer.
an anagram of 'bert' is 'brte' which is present in the left over letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for brute that I've seen before include "Wild animal" , "Nasty person, a real beast" , "Cruelly rapacious person" , "Savage person" , "Vicious type" .)