The Collaborative International Dictionary of English v.0.48:
Shallow \Shal"low\, a. [Compar. Shallower; superl.
Shallowest.] [OE. schalowe, probably originally, sloping or
shelving; cf. Icel. skj[=a]lgr wry, squinting, AS. sceolh, D.
& G. scheel, OHG. schelah. Cf. Shelve to slope, Shoal
1. Not deep; having little depth; shoal. "Shallow brooks, and
rivers wide." --Milton.
2. Not deep in tone. [R.]
The sound perfecter and not so shallow and jarring.
3. Not intellectually deep; not profound; not penetrating
deeply; simple; not wise or knowing; ignorant;
superficial; as, a shallow mind; shallow learning.
The king was neither so shallow, nor so ill
advertised, as not to perceive the intention of the
French king. --Bacon.
Deep versed in books, and shallow in himself.