Crossing a line in pursuit of farceur (9)
I believe the answer is:
traversal
'crossing' is the definition.
(I know that traversal is a type of crossing)
'a line in pursuit of farceur' is the wordplay.
'line' becomes 'l' (used when specifying particular lines from a poem).
'in pursuit of' is a charade indicator (letters next to each other) (some letters chase after others).
'farceur' becomes 'travers' (I've seen this before).
'a'+'l'='al'
'al' put after 'travers' is 'TRAVERSAL'.
(Other definitions for traversal that I've seen before include "Coming across" , "A crossing (of something)" , "A journey across" , "Act of crossing" , "crossing over bridge" .)