decorous

adjective2

1. •
   Marked by behaviour, manners, etc., regarded as proper, tasteful, and in accordance with accepted standards; becoming, seemly.

   • [S]ome grumbling voice, / Which now and then will make a slight inroad / Upon decorous silence, […] — 1822
2. •
   (no longer used) Appropriate, suitable.

   • [B]oth the truth vvhich the Prophecy aims at is faithfully conveyed, and that decorous embellishment in the external Cortex of the Prophecy punctually observed. — 1664