tincture, n. — Green’s Dictionary of Slang

tincture n.

[hugely popularized by the ‘Dear Bill’ column in the magazine Private Eye, lampooning Denis Thatcher (1915–2003), husband of prime minister Margaret Thatcher (b.1925)]

a drink.

1910		Truth (Brisbane) 4 Dec. 11/3: He clutched a heavy weight amber-drench, and I the extensively advertised tired-bloke’s tincture.
1914		Joyce ‘Counterparts’ Dubliners (1956) 92: Weathers made them all have just one little tincture at his expense.
1979		H. Leonard A Life (1981) Act II: You’ll have a tincture.
1985		A. Payne ‘Minder on the Orient Express’ Minder [TV script] 76: Think that little French garcon would get us a tincture?