Green’s Dictionary of Slang

-ster sfx

[ult. ME, where it represents nouns of action; in SE such terms include jokester, trickster, punster etc. Recent sl. uses have adopted the sfx, adding it to a surname or nickname and prefixing that with the, e.g. the US wrestler ‘Hulk’ Hogan is The Hulkster etc]

[late 17C+] a sfx implying agency.