El, perhaps — and where it terminates? (3,2,3,4)
I believe the answer is:
end of the line
'terminates?' is the definition.
I know nothing about this answer so I can't judge whether this works.
'el perhaps and where it' is the wordplay.
I cannot really understand how this works, but
'el' is within the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is found in the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for end of the line that I've seen before include "Point impossible to pass" , "Point beyond which one cannot continue" , "Point beyond which it is useless or impossible to proceed" , "After this, one can no longer survive" , "The final point" .)