One who may fancy a half of beer? (7)
I believe the answer is:
dreamer
'one who' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'fancy a half of beer?' is the wordplay.
'fancy' becomes 'dream' (both can mean a fantasy).
'a half of' means to take half the letters.
'beer' cut in half is 'er'.
'dream'+'er'='DREAMER'
'may' is the link.
Can you help me to learn more?
(Other definitions for dreamer that I've seen before include "description of an Oxford spire?" , "One who tends to live in an unreal world" , ""You may say I'm a __" (John Lennon)" , "One fantasising" , "Romantic" .)