We're paying for liability (4)
I believe the answer is:
onus
'for liability' is the definition.
(I've seen this in another clue)
I don't understand the remainder of the clue.
(Other definitions for onus that I've seen before include "'Burden, load (4)'" , "Responsibilty" , "albatross?" , "Burden, duty" , "Weight of responsibility" .)