Book about swine running over couple (7)
I believe the answer is:
twosome
'couple' is the definition.
(I know that couple can be written as twosome)
'book about swine running over' is the wordplay.
'book' becomes 'tome' (a tome is a book).
'about' indicates putting letters inside.
'swine' becomes 'sow' (sow is a kind of swine).
'running over' says the letters should be written in reverse (the letters turn over to the opposite direction).
'sow' written backwards gives 'wos'.
'tome' going around 'wos' is 'TWOSOME'.
(Other definitions for twosome that I've seen before include "game of golf" , "Couple" , "Pair, duo" , "Item" , "match" .)