Body odour countered by sitting in Calvin Klein perfume (9)
I believe the answer is:
obsession
'calvin klein perfume' is the definition.
(I've seen this in another clue)
'body odour countered by sitting' is the wordplay.
'body odour' becomes 'bo' (synonyms).
'countered' shows that the letters should be reversed in order (I've seen 'counter' mean this).
'by' means one lot of letters go next to another.
'sitting' becomes 'session' (eg a parliamentary session).
'bo' backwards is 'ob'.
'ob'+'session'='OBSESSION'
'in' is the link.
(Other definitions for obsession that I've seen before include "Extreme interest" , "All-consuming idea" , "Fan may display this" , "Continual preoccupation" , "All-absorbing idea" .)