Synonyms for Matte:

adj.

dull (adjective)
leaden, subdued, dusky, flat, muted.
flat (adjective)
weak.

n.

dusky, wan, subdued, muted, weak, leaden. matte (noun)
lusterlessness, matted, flat, mat, flatness, dull, matt, lustrelessness.

Other synonyms:

adj.
dull, flat.