Possibility that doctor is kissing nurses (4)
I believe the answer is:
risk
'possibility' is the definition.
'doctor is kissing nurses' is the wordplay.
'nurses' indicates a hidden word (nurse can mean holding closely).
'RISK' is hidden in the letters of 'doctor is kissing'.
'that' acts as a link.
(Other definitions for risk that I've seen before include "Gamble" , "Jeopardy" , "Danger or hazard" , "Expose to danger" , "Assessment of potential dangers -- any silk saris (anag)" .)