IPA: //ˈdɛkərəs//
KK: /ˈdɛkərəs/
Showing good manners and proper behavior; socially acceptable and appropriate.
The decorous guests followed the formal dress code for the event.
Comparative: more decorous
Superlative: most decorous
Decorous → It is formed from "decorus" (from Latin, meaning proper, seemly) and the suffix "-ous" (meaning full of). The word "decorous" means full of propriety or behaving in a proper manner.
Think of 'decorus' meaning proper, and remember that 'decorous' describes someone who behaves in a proper or seemly way.