1. (a.) Feeble in mind; complacently foolish\; weak; silly; stupid; foolish; fatuitous.

2. (a.) Without reality; illusory, like the ignis fatuus.

absurd air-built airy apish asinine barren batty befooled beguiled besotted blank blankminded bootless brainless buffoonish calm catchpenny chimerical cloud-built cockeyed counterproductive crazy credulous daffy daft dazed dizzy doting dreamlike dumb effete empty empty-headed ethereal etiolated fanciful fatuitous feckless flaky flimsy fond fool foolheaded foolish fribble fribbling frivolous frothy fruitless fuddled futile gaga gaseous goofy gossamery gulled hollow idiotic idle illusory imaginary imbecile inadequate inane incogitant ineffective ineffectual inefficacious inept infatuated inoperative insane insensate invalid kooky light loony mad maudlin moronic nirvanic nugacious nugatory nutty oblivious of no force otiose passive phantomlike quietistic rarefied relaxed sappy screwy senseless sentimental shadowy shallow silly slender slight spirituous sterile stupid subtile subtle superficial tenuous thoughtfree thoughtless tranquil trifling trite trivial unavailing unideaed unintellectual unoccupied unreal unreasoning unthinking unwitty useless vacant vacuous vain vapid vaporous wacky weak-minded wet windy witless