Crooked as a dog's hind leg simile
Very dishonest and deceptive
Don't play cards with Tom. He's as crooked as a dog's hind leg.
I advised Mary shouldn't put her trust in Tony. He's as crooked as a dog's hind leg.
To be dishonest or deceptive and no one can believe
It is impossible for a person to change his or her innate or fundamental nature.
He said he would quit alcohol, but he still can't desist from drinking. Once an alcoholic, always an alcoholic.