Q: Is an official a person who is an official by virtue of an election? ¶
A: Yes.
Q: Is an official an official of central or local government? ¶
A: Yes.
Q: Is an official used to describe a person enforcing playing rules in the capacity of a linesman, referee and umpire? ¶
A: Yes, also specified by the discipline, e.g. American football official, Ice hockey official.
Q: Is an official an antonym? ¶
A: Yes, and variously may mean informal, unrecognised, personal or unacknowledged.