Suspense is on the rise in joint (7)
I believe the answer is:
tension
'suspense' is the definition.
(I've seen this before)
'is on the rise in joint' is the wordplay.
'on the rise' says the letters should be written in reverse.
'in' is an insertion indicator.
'joint' becomes 'tenon' (I've seen this in other clues).
'is' reversed gives 'si'.
'si' going inside 'tenon' is 'TENSION'.
(Other definitions for tension that I've seen before include "anxious state" , "Intones (anag) - stress" , "nerves" , "Strained state" , "Stretched state" .)