Adam, as described by George, is a venerable fellow (4)
I believe the answer is:
bede
'a venerable fellow' is the definition.
The definition suggests a singular noun which matches the answer.
'adam as described by george is' is the wordplay.
I cannot really see how this works, but
'is' could be 'be' and 'be' is present in the answer.
The remaining letters 'de' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for bede that I've seen before include "venerable person?" , "Venerable scholar" , "'Venerable' English monk" , "old monk" , "Anglo-Saxon historian" .)