If using "shady" toward a person sounds bit rude, what else could I use to express someone is "dark-sided"?
Native speaker’s answer
Rebecca
Some other words you can use to express that someone has a "dark side" that don't sound rude are "suspicious" and "untrustworthy". Keep in mind that telling anyone directly that they are "suspicious" or "untrustworthy" could be considered rude in Western culture, but these terms are appropriate to use when to talking about another person not involved in the conversation. Ex: The person walking around at night trying to open doors seems suspicious. Ex: My roommate is untrustworthy because she steals my things when I'm gone.