I wish now we hadn't let old Mary go, even though she was so undependable about thorough-cleaning.

He's a witch with horses and knows he's always got a job if he wants it, and I reckon that makes him kind of undependable about staying in any one place long at a time.

The very institution of slavery itself produced shiftless, undependable beings, seeking relief whenever possible by giving the least and getting the most from their masters.