Inducing sleep (9)
I believe the answer is:
soporific
'inducing sleep' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for soporific that I've seen before include "making one nod" , "Inducing mental lethargy" , "Sleep-inducing" , "Sedative" , "Inducing drowsiness or sleep" .)