Green’s Dictionary of Slang

fig n.³

In phrases

in full fig (also full fig) [SE fig out, to dress up; but note feague v. (2)/fig (a horse) v.]

dressed up.

1836		M. Scott Cruise of the Midge II 280: In front of this shed – full fig, in regular Highland costume [...] marched the bagpiper.
1841		Bristol Mercury 26 June 2/6: They were all drawn up in the waist 'in full fig' their cracked hats profusely decorated.
1843		T. Haliburton Sam Slick in England I 243: I rigs up this morning, full fig, calls a cab, and proceeds in state to our embassy.
1845		R.S. Surtees Hillingdon Hall III 228: The whole establishment were full fig to receive him.
1850		(con. 1843) Melville White-Jacket (1990) 96: Matchless Jack, in full fig, bowed again and again, with true quarter-deck grace and self-possession.
1861		T. Hughes Tom Brown at Oxford (1880) 8: He waits on me in hall, where we go in full fig of cap and gown at five, and get very good dinners, and cheap enough].
1874		E.K. Wood Johnny Ludlow I 109: When our church bells were going for service, Major Parrifers carriage turned out with the ladies all in full fig.
1885		Bulletin (Sydney) 16 May 6/2: The funniest part […] was where a low comedy artist from Sydney, who turned up at the ‘function’ coatless and in a broad-brimmed hat while all other hands were in full fig, indulged in some characteristic pranks.
1892		F. Remington letter 5 Jan. in Splete (1988) 241: It is very rare that soldiers do live up to the awful possibilities of the ‘full fig’.
1896		Worcs. Chron. 29 Feb. 4/4: He followed this up with a course of running and jumping [...] in 'full fig'.
1909		J. Ware Passing Eng. of the Victorian Era 193/2: Peacock (Anglo-Indian). Walk up and down in full fig while the band plays.
1924		Galsworthy White Monkey 29: Rather! Full fig or dinner jacket?
1935		E.F. Benson Mapp and Lucia (1984) 124: Very distressing too, it was to see Lucia in full fig as Queen Elizabeth.
1955		Picture Post 26 Mar. 50: Julie Colbert [...] and her escort Marty Topscott, in full fig.
1997		(con. 1916) D. Farson Never a Normal Man 15: All our embassy were there in full fig.
2002		Indep. on Sun. 21 July 23: Upper Eastside dames in full fig riding the 7 subway train to Queens.