Jejune
Part of speech: adjective
Definition: Not nutritious. Lacking matter; empty; devoid of substance. Naive; simplistic.
Uninteresting
Part of speech: adjective
Definition: Arousing little or no interest; boring or uneventful.
Example sentence: There's barely any aspect of our modern lives that hasn't had a mathematical contribution at some point and yet, if you asked the average person, they might think that maths is just difficult, irrelevant and uninteresting.