Dry man, does he count all the holes, except the nineteenth, of course? (11)
I believe the answer is:
teetotaller
'he count all the holes except the nineteenth of course?' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'dry man does' is the wordplay.
'dry' becomes 'teetotal' (synonyms).
'man does' becomes 'ler' (I can't explain this - if you can you should believe this answer much more).
'teetotal'+'ler'='TEETOTALLER'
Can you help me to learn more?
(Other definitions for teetotaller that I've seen before include "as observant Muslim, say" , "Abstainer from drink" , "One dry" , "Abstainer from alcohol" , "Rechabite" .)