buy a pig in a poke
porcus, pig, and piscis, fish; the mod.
If I promise not to act like a misogynist pig, would you have dinner with me?
Oh, what a pig I am! he repeated, flushing suddenly.
She brought her lips to his ear and rasped softly, "I'll be dipped in shit before I let a misogynist pig like you lay a hand on me."