Arguing about mere squalor developing (11)
I believe the answer is:
quarrelsome
'arguing' is the definition.
('quarrelsome' can be a synonym of 'arguing')
'mere squalor developing' is the wordplay.
'developing' indicates anagramming the letters.
'mere'+'squalor'='meresqualor'
'meresqualor' anagrammed gives 'QUARRELSOME'.
'about' is the link.
(Other definitions for quarrelsome that I've seen before include "Disputatious, argumentative" , "Combative" , "Belligerent - queer morals (anag)" , "contentious" , "up for scrap?" .)