Definition of "Shady" :

adjective: filled with shade

"The shady side of the street."

adjective: of questionable honesty or legality

"He established a dummy company through which he laundered vast sums of cash from shady middlemen and arms dealers."

adjective: not as expected

"A shady deal."

adjective: quiet, dark, or concealed

"Her shady past intrigued him."