He may have a chapter to himself (4)
I believe the answer is:
dean
'he may have a chapter to himself' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he may have a' is the wordplay.
'he may' becomes 'de' (I can't explain this - if you can you should believe this answer much more).
'have' says to put letters next to each other.
'a' becomes 'an'.
'de'+'an'='DEAN'
Can you help me to learn more?
(Other definitions for dean that I've seen before include "Kind of clergyman or university official" , "James ..., film star famous for his moody rebellious roles" , "Small valley - cathedral dignitary" , "Church or college dignitary" , "College officer" .)