Straight from the mouths of babes

Stupid: -adjective
1. Lacking ordinary quickness and keenness of mind; dull.
2. Characterized by or proceeding from mental dullness; foolish; senseless.
3. Tediously dull, esp. due to lack of meaning or sense; inane; pointless.
4. Annoying or irritating; troublesome.
5. In a state of stupor; stupefied.
6. Slow to learn or understand; obtuse.
7. Tending to make poor decisions or careless mistakes.
8. Marked by a lack of intelligence or care; foolish or careless.
9. Pointless, worthless.

-noun
6. Informal. a stupid person.

-Related forms
stupidly, adverb
stupidness, noun
unstupid, adjective
unstupidly, adverb
unstupidness, noun

Synonyms: brainless, dazed, deficient, dense, dim, doltish, dopey, dull, dumb, dummy, foolish, futile, gullible, half-baked, half-witted, idiotic, ill-advised, imbecilic, inane, indiscreet, insensate, irrelevant, laughable, loser, ludicrous, meaningless, mindless, moronic, naive, nonsensical, obtuse, out to lunch, pointless, puerile, rash, senseless, shortsighted, simple, simpleminded, slow, sluggish, stolid, stupefied, thick, thick-headed, trivial, unintelligent, unthinking, witless.

I am all of these things. Take your pick.