Synonyms for Obtuse:

adj.

blunt (adjective)
pointless, rounded, unpointed, unsharpened, blunt, dull.
blunt, not sharp (adjective)
round, rounded.
dull (adjective)
apathetic, benumbed, besotted, blunt, boorish, bovine, cloddish, comatose, dense, dim, doltish, drowsy, dull, lethargic, loutish, ponderous, sleepy, slow, sluggish, soporific, stupefied, thick-witted, unpointed.
indiscreet (adjective)
indiscreet, insensitive, tactless, undiscerning, unselective.
slow to understand (adjective)
dense, dopey, dull, dumb, insensitive, stolid.
thoughtless (adjective)
undiscerning.

n.

idiotic, silly, simple-minded. cos, cosine, cotangent, degree, median, minute, oblique, orthogonal, perpendicular, round. ability, blockheaded, dopey, thickheaded, dimwitted, hebetudinous. not sharp (noun)
blunt, dull, round.
obtuse (noun)
dense, dim, dull, dumb, purblind, simple, slow, undiscerning, unsubdivided.
stupid (noun)
insensible, stolid.

Other synonyms:

blockheaded, cos, cosine, cotangent, orthogonal, dimwitted. dopey, thickheaded, hebetudinous. perpendicular. degree, median, oblique. minute. Other relevant words:
blockheaded, cos, cosine, cotangent, degree, dopey, dumb, idiotic, insensible, minute, oblique, perpendicular, purblind, round, silly, simple, simple-minded, stolid, thickheaded, unsubdivided, dimwitted, hebetudinous.

Usage examples for obtuse

  1. Perhaps I am obtuse but it seems to me that this is your design, not mine. – The Orchard of Tears by Sax Rohmer
  2. It may form an obtuse angle with the cross- head journal when so viewed. – Modern Machine-Shop Practice, Volumes I and II by Joshua Rose
  3. It is needless to continue the tale; the reader cannot be so obtuse as not to notice the moral of it. – Primitive Love and Love-Stories by Henry Theophilus Finck