Green’s Dictionary of Slang

of a man, to adorn oneself, to dress up.

1611		R. Cotgrave Dict. of Fr. and Eng. Tongues n.p.: adoniser to adonise it; to resemble Adonis, to imitate or counterfeit the graces, or beautie of Adonis.
1749		Smollett (trans.) Adventures of Gil Blas III 418: Three good hours, at least, in adjusting and adonising myself.
1818		S.E. Ferrier Marriage I 96: ‘Venus and the Graces, by Jove!’ exclaimed Sir Sampson [...] ‘now I must go and adonise a little myself.’.
1823		[C.M. Westmacott] Mammon in London 1 191: [B]attered beaux, adonised, and patched up for the evening.
1846		Swell’s Night Guide 107/1: Adonizing, faking the mug, and flashing the togs, doing the swellman, nutting the donnas, and queering the greens, to beautify, to appear as Adonis.
1850		F.E. Smedley Frank Fairlegh (1878) 346: He positively refused to face the ladies till he had changed his shooting costume, so I left him up at the Hall to adonize.
1865		Pall Mall Gazette 11 Aug. 9/2: They may be adonizing at Truefit’s [F&H].