Blunt

1. Having a thick edge or point; not sharp.
2. Dull in understanding; slow of discernment; opposed to acute.
3. Abrupt in address; plain; unceremonious; wanting the forms of civility; rough in manners or speech.
4. Hard to impress or penetrate.
5. Slow or deficient in feeling: insensitive.

(having a thick edge or point): dull, pointless, coarse

(dull in understanding): stupid, obtuse

(abrupt in address): curt, short, rude, brusque, impolite, uncivil, harsh