know (something) off pat(redirected from know something off pat)
know (something) off pat
To learn, master, or understand something perfectly, to the point of requiring little or no focus to do, recall, or accomplish it. I know it's a little tricky getting the hang of the machine, but keep at it, and you'll know it off pat in no time. My sister is such a musical prodigy that she can know a song off pat after listening to it only once or twice.