He's known for his originality (4)
I believe the answer is:
adam
This might be a double definition.
'he's' is the first definition.
'known for his originality' is the second definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
Can you help me to learn more?
(Other definitions for adam that I've seen before include "One of our common ancestors?" , "neoclassical style" , "man expelled from garden" , "father of us all?" , "Fellow" .)