Decorous (adjective)
decorous [dek-er-uh s, dih-kawr-uh s, -kohr-]

adjective
1. characterized by dignified propriety in conduct, manners, appearance, character, etc.

Synonyms
See more synonyms on Thesaurus.com
proper, becoming.

Antonyms
undignified.

Origin: 1655–65; < Latin decōrus seemly, becoming, derivative of decus; see decorate, -ous

Now YOU come up with a sentence (or fic? or graphic?) that best illustrates the word.