Green’s Dictionary of Slang

yadnab n.

brandy.

1859, 1860		Hotten Dict. of Modern Sl. etc.
1873		Sl. Dict.
1882		Sydney Sl. Dict. (2 edn) 11: Yadnarb - Brandy.
1891		Exeter & Plymouth Gaz. 15 Oct. 6/4: An adjournment is made for ‘yodak,’ i.e., a brandy drink.
1933		‘William Juniper’ True Drunkard’s Delight 230: Brandy is your nectar and you shout for [...] yadnarb.