empty, inane, meaningless, senseless

frivolous, inconsequential, inconsiderable, insignificant, little, minor, negligible, slight, trifling, trivial, unimportantabsurd, asinine, balmy, brainless, crackpot, crazy, cuckoo, daffy, daft, dotty, empty-headed, fatuous, foolish, half-witted, harebrained, insane, jerky, kooky(also kookie), loony(also looney), lunatic, mad, mindless, nonsensical, nutty, preposterous, sappy, silly, simpleminded, stupid, tomfool, unintelligent, unwise, wacky(also whacky), weak-minded, witless, zanyirrational, unreasonableaimless, haphazard, purposeless

meaningful, significant

eloquent, expressive, pregnant, revealing, suggestive, tellinglogical, rational, reasonable, validconsequential, eventful, important, key, major, momentous, substantial, weighty