condescend

(verb) behave in a patronizing and condescending manner.

(verb) do something that one considers to be below one's dignity. Synonyms: deign, descend.

(verb) debase oneself morally, act in an undignified, unworthy, or dishonorable way. Synonyms: stoop, lower oneself. Example: "I won't stoop to reading other people's mail."

(verb) treat condescendingly. Synonyms: patronize, patronise.