lacking sense, significance, or ideas; silly

inane questions.

empty; void.

something that is empty or void, esp. the void of infinite space.

adjective

bright , intelligent , smart

adjective

absurd , asinine , daft , empty , fatuous , flat , foolish , frivolous , futile , harebrained * , idiotic , illogical , imbecilic , innocuous , insipid , jejune , laughable , meaningless , mindless , pointless , puerile , ridiculous , sappy * , senseless , silly , trifling , unintelligent , vacant , vacuous , vain , vapid , weak , wishy-washy * , worthlessnotes:inane means silly , lacking significance or insubstantial; insane means mentally deranged , mad or very foolish , blank , empty-headed , dumb , fatuitous , feckless , imbecile , insubstantial , nonsensical , shallow , stratospheric , stupid , void , worthless