(Thanks to Nancy Friedman.) Evasive, tricky, artful; dubious, unreliable. OED’s first citation is 1861. Google Ngrams show British use taking off in about 1940 and American, characteristically for NOOBs, circa 1990.
To heighten the fun of the chase, she gives Grace a road buddy in Darcy Kohler, a dodgy market analyst who stands to lose her condo if her missing boyfriend can’t be found to make good on the bond she co-signed. (Marilyn Stasio, New York Times, September 18, 1988)/ I see that the administration is pressing New York’s attorney general to drop its investigation into dodgy foreclosure practices and settle with the banks. (Megan McArdle, TheAtlantic.com, August 25, 2011)