Disguise

There’s that old saying: wolf in sheep’s clothing.
That is one of them. Some persons require a disguise to pass for a normal Joe in order to hide, avoid detection, and have a defence for their actions. Sexual predators, paedophiles, and to a lesser level psychopaths and sociopaths—though it's important to remember that the majority of these individuals aren't harmful. Psychopaths are typically quite skilled at hiding so that other people don't feel uncomfortable; you probably know a few of them without even realising it.

However, keep in mind that it can also operate in reverse. sheep dressed like wolves.
People who are so uneasy or nervous, hurt or damaged that they must act normal in order to function in society. People who have a hard time making friends or who have experienced terrible catastrophes but put on a grin to blend in.

You dress up to blend in. Sometimes it's more crucial to understand why someone is hiding something than what they are actually concealing. You can typically determine whether you should be cautious of someone by understanding their demeanour but that they are hiding something.