Green’s Dictionary of Slang

mildly drunk, tipsy.

c.1800		‘Drunk in the Night’ No. 26 Papers of Francis Place (1819) n.p.: He is one of our party, says he, and he’s hearty.
1824		J. Wight Mornings in Bow St. 143: ‘I was hearty —but not drunk by no manes — bekase I’d only three pots of the beer, and a small drop of the gin’.
1833		W. Carleton Traits and Stories of Irish Peasantry III 370: Why, they’re hearty* as it is, the sinners (*Tipsy).
1937–84		Partridge DSUE (1984) 543: [...] ca. 1850–1915.