if one knows what’s good for one

if (one) knows what's good for (one)

If one wants to avoid trouble (one will do or avoid a certain thing). Oh, you'll be on time for the meeting, if you know what's good for you. If he knows what's good for him, he'll stop calling me that.See also: good, if, know

if one knows what’s good for one

phr. one had better do what is expected of one. You’d better be on time if you know what’s good for you. See also: good, if, know, one