Green’s Dictionary of Slang

improper, of improper character.

1812		G. Colman Yngr ‘Two Parsons’ in Poetical Vagaries 115: What would become of all the fie-fie Ladies? And all the Proprietors of paw-paw Houses?
1821		‘An Amateur’ Real Life in London I 386: This is a method which the Church-wardens of parishes sometimes take of shaming the pa-pa or fie fie ladies from their residences, or at least of discovering their visitors.
1851		Bell’s Life in Sydney 8 Nov. 3/2: The girl had been placed with Mrs Cox upon the understanding that she was a milliner and dress-maker, but [...] on the contrary. Mrs C. was mistress of a fie-fie establishment.
1861		Trollope Framley Parsonage (1866) 55: She had sometimes to whisper to Miss Dunstable, for there were one or two fie-fie little anecdotes about a married lady, not altogether fit for young Mr. Robarts ears.
1879		London Life 28 June 7/2: The denizens of loosish haunt, / Where fie-fie work a lot there is.
1885		Bulletin (Sydney) 15 Aug. 20/2: The Delilah, a fie-fie, florid, flashy grass-widow, who flaunted her ‘aureoline tresses,’ her powdered-painted cheeks, her kohl’d eyes, and her pinched-in waist on the quarter-deck, on sunny Sabbath mornings.
1891		‘’Arry on Wheels’ in Punch 7 May 217/2: It’s only the stuckuppy sort as consider it rude or fie-fie.
1903		J. Furphy Such is Life 211: Socially, she knew something fie-fie about most of our old nobility.