Squabbling, are lined up (2,1,3)
I believe the answer is:
in a row
'are lined up' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for in a row that I've seen before include "Lined up" , "successively" , "Consecutively" , "arguing?" , "fighting" .)