buckeen, n. — Green’s Dictionary of Slang

buckeen n.

[Anglo-Irish buckeen, a younger son of the impoverished Anglo-Irish aristocracy. The term apes the better-known squireen, a petty landowner]

a bully.

1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1797		M. Leeson Memoirs (1995) III 190: In consequence of [...] some buckeens there, that became troublesome, we resolved to shift the scene, and return to Pitt-street.
1811		Lex. Balatronicum.
1825		T.C. Croker Fairy Legends and Traditions of the South of Ireland (1862) 327: Manus O’Rourke, a great buckeen, a cock-fighting, drinking blackguard that was long ago.