1.Definition: filled with shade

"The shady side of the street"

Related Adjective(s):shadowed, shadowy, umbrageous

2.Definition: not as expected

"A shady deal"

Related Adjective(s):fishy, funny, suspect, suspicious

3.Definition: of questionable honesty or legality

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

4.Definition: quiet, dark, or concealed

"Her shady past intrigued him", "A shady part of town"