Ill-mannered clamour about pop group curtailed (6)
I believe the answer is:
crabby
'ill-mannered clamour about pop group curtailed' is the definition.
I can't judge whether this defines the answer.
'mannered clamour about pop group curtailed' is the wordplay.
'mannered clamour' becomes 'cry' (clamour can mean to cry or yell. I am not sure about the 'mannered' bit.).
'about' is an insertion indicator.
'pop group' becomes 'abba' (I've seen this before).
'curtailed' means to remove the last letter.
'abba' with its last letter removed is 'abb'.
'cry' enclosing 'abb' is 'CRABBY'.
Can you help me to learn more?
(Other definitions for crabby that I've seen before include "Cantankerous like crustacean" , "Sour-tempered like common crustacean" , "In bad temper" , "Temperamental" , "Ill-natured" .)