Group from the ’80s and Blur in trouble (7)
I believe the answer is:
madness
'group from the '80s' is the definition.
I can't tell whether this definition defines the answer.
'and blur in trouble' is the wordplay.
'blur' indicates anagramming the letters (blur can mean a confusion or mess).
'in' indicates putting letters inside.
'trouble' becomes 'mess'.
'and' is an anagram of 'adn'.
'adn' inserted into 'mess' is 'MADNESS'.
(Other definitions for madness that I've seen before include "Lunacy - ska/pop band" , "Dementia" , "fury" , "great anger" , "Folly" .)