decorous
Meaning: socially proper, appropriate
Usage: The appreciative guest displayed decorous behavior toward his host.
ingenuous
Meaning: not devious; innocent and candid
Usage: He must have writers, but his speeches seem so ingenuous it’s hard to believe he’s not speaking from his own heart.
innocuous
Meaning: harmless, inoffensive
Usage: In spite of their innocuous appearance, these mushrooms are actually quite poisonous.
reputable
Meaning: of good reputation
Usage: After the most reputable critic in the industry gave the novel a glowing review, sales took off.
propriety
Meaning: the quality or state of being proper, decent
Usage: The principal questioned the propriety of discussing private information in public.