1. Decorous(Adjective): polite and dignified
An Example: You could have been more decorous in your dealings with your client.
2. Decrepit(Adjective): Old and weak
An example: I will give a facelift to the decrepit sugar factory when voted into power.
3. Demure(Adjective): shy and modest
An Example: Jane can be hyperactive in one minute, then mysteriously demure in the next minute.