To develop bad habits; to behave improperly or illegally.
If you keep hanging out with that gang you'll go astray.
To behave in an adulterous manner.
The woman thought her husband had gone astray.
To come to believe an untruth.
(of an object) To become lost or mislaid.
(chiefly in the negative) To be undesirable or unhelpful.
A pinch of salt in this dish wouldn't go astray.