On tenterhooks, but has the intelligence to cover what distinguishes their product (8)
I believe the answer is:
suspense
'product' is the definition.
The answer and definition can be both related to thinking as well as being singular nouns.
Maybe they are linked in a way I don't understand?
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for suspense that I've seen before include "Uneasy uncertainty" , "State of apprehension about what's going to happen" , "Hitchcock's speciality" , "Pre-climactic excitement" , "Uncertainty and apprehension about what's going to happen" .)