WordNet sense 1 (of little substance or significance):

trivial

WordNet sense 2 (not important or noteworthy):

insignificant, unimportant

WordNet sense 3 (lacking depth of intellect or knowledge; concerned only with what is obvious):

shallow

WordNet sense 4 (marked by lack of intellectual depth):

glib

WordNet sense 5 (appearing as such but not necessarily so):

apparent, ostensible

WordNet sense 6 (involving a surface only):

skin-deep, surface