Burden — and where it might fall (4)
I believe the answer is:
onus
'burden' is the definition.
(I know that burden can be written as onus)
'and where it might fall' is the wordplay.
I cannot really see how this works, but
'and' could be 'n' (common abbreviation for 'and') and 'n' is found within the answer.
The remaining letters 'ous' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for onus that I've seen before include "albatross?" , "'Responsibility, task or burden (4)'" , "Encumbrance" , "'Burden, load (4)'" , "Weight of responsibility" .)