What is the meaning of Shifty?

Subject to frequent changes in direction.

Moving from one object to another; not looking directly and steadily at the person with whom one is speaking.

Having the appearance of being dishonest, criminal, or unreliable.

Resourceful; full of, or ready with, shifts or expedients.

Thomas Wright, Dictionary of Obsolete and Provincial English, London: Henry G. Bohn, Volume 2, p. 848: “Cunning; artful” (Craven [Yorkshire]).

Source: wiktionary.org