A moniker is a nickname or pet name for a person. People who are dating or friends often have monikers like “Sweetie”, “Honey” etc.
Some monikers are shortened versions of your name, like “Ed” or “Eddie” for “Edward.” Athletes and other famous people have many monikers.
>”Hoosier” is a common moniker for a resident of Indiana.
> I think Happy is an appropriate moniker for someone who smiles so much.