Buddhist Dictionary of Pali Proper Names by G P Malalasekera
Udakarahada Sutta
Udakarahada Sutta:There are four kinds of sheets of water:
(1) Flat (uttāna) but deep in appearance (obhāsa); (2) deep but flat in appearance; (3) flat and flat in appearance; (4) deep and deep in appearance.So,also,there are four classes of people:
handsome in appearance but shallow in mind; not handsome in appearance but deep in knowledge; neither handsome nor wise; both handsome and wise (A.ii.105-6).