It describes a man who lacks spirit (8)
I believe the answer is:
teetotal
'it describes a' is the definition.
The definition suggests a singular noun but the answer is not.
'man who lacks spirit' is the wordplay.
I cannot really understand how this works, but
'man' could be 'al' (man's name) and 'al' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for teetotal that I've seen before include "Completely abstinent" , "Abstention from alcoholic drink" , "Non-drinking" , "Completely dry" , "Abstinent from alcohol" .)