Nervous or excited uncertainty (8)
I believe the answer is:
suspense
'nervous or excited uncertainty' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for suspense that I've seen before include "Alfred Hitchcock was the master of it" , "Uncertainty and apprehension about what's going to happen" , "State of anxiety or excitement" , "The 3 of having to wait" , "State of uncertainty about the future" .)