Green’s Dictionary of Slang

(Irish) illicitly distilled whisky, poteen.

1797		M. Leeson Memoirs (1995) III 144: I [...] had them properly plied all night, with the pure native.
1821		‘A Real Paddy’ Real Life in Ireland 138: Peg Wither and Grin toddled out, and soon returned with black jack full of the real native.