WordNet sense 1 (of little substance or significance):

trivial

WordNet sense 2 (having little importance):

light

WordNet sense 3 (not important or noteworthy):

unimportant

WordNet sense 4 (signifying nothing):

unmeaning

WordNet sense 5 (having no meaning or direction or purpose):

meaningless, nonmeaningful

WordNet sense 6 (of little importance or influence or power; of minor status):

peanut

WordNet sense 7 (of lesser importance or stature or rank):

minor

WordNet sense 8 (not worthy of notice):

undistinguished

WordNet sense 9 (too small or unimportant to merit attention):

inconsiderable