Stereotyping is the act itself: treating everyone in a group as if they were all the same, and then judging one person by that group picture instead of by what that person is actually like. It works both as an -ing noun ('racial stereotyping', 'stereotyping in the media', 'this is stereotyping') and as the ongoing form of the verb ('you are stereotyping her'). Two things are worth noticing. First, it names an action, so it can be accused: 'That's stereotyping.' is a complete, sharp thing to say to someone, and it stings a little — it says you have stopped seeing the individual. Second, the picture does not have to be nasty for it to count. 'Asian students are good at maths' sounds like a compliment, but it is still stereotyping, because it decides about a person before meeting them and leaves no room to be otherwise. Teachers, HR departments and news writers use this word a lot; it turns up constantly next to words like racial, gender, cultural, negative, and in phrases like 'avoid stereotyping'. In everyday chat, people are more likely to say 'don't put people in boxes', which is the same idea in plainer clothes.