agnomen
/æɡˈnoʊmən/
noun
- An additional name or title that describes a person's character, achievements, or appearance, often given as a nickname.
- Her friends gave her the agnomen 'the Brain' because she always solved puzzles first.
- In ancient Rome, a successful commander might receive an agnomen like 'Africanus'.
- The general earned the agnomen 'the Great' after his victories.