A person or object that could be considered very unreliable, unpredictable, tricky, deceitful, and/or questionable. Can quickly go from good to bad/ cooperative to fuckey. Basically a fun way to call a person or object an all around bastard.
1.) My car randomly breaks down on me, it's such a Shifty McFickle.
2.) Timmy doesn't give a damn about anyone but himself, he is just a Shifty McFickle.