Nouns

(n)shoal, shallowa stretch of shallow water

Verbs

(v)shallow, shoalmake shallow“The silt shallowed the canal”
(v)shallow, shoalbecome shallow“the lake shallowed over time”

Adjectives

(a)shallowlacking physical depth; having little spatial extension downward or inward from an outer surface or backward or outward from a center“shallow water”, “a shallow dish”, “a shallow cut”, “a shallow closet”, “established a shallow beachhead”, “hit the ball to shallow left field”
(a)shallownot deep or strong; not affecting one deeply“shallow breathing”, “a night of shallow fretful sleep”, “in a shallow trance”
(s)shallowlacking depth of intellect or knowledge; concerned only with what is obvious“shallow people”, “his arguments seemed shallow and tedious”