So I have just started to learn some 成语 but I came across a 成语 that is 高人一等. I was just wondering what it means, and where it could have come from. From context clues, I think it has to do with tall people or people that are higher(hierachy?), but I am not too sure if I'm on the right track. Thanks for the help!
First of all, 高 doesn't only mean high or tall. 高 also figuratively means good, smart, superior and so on. E.g. 高招 (smart move), 高人 (a person who has very good idea).
so, 高人一等，literally means 比别人高一个等级，which figuratively means better than/superior to other people.
It can be used both positive and negative ways. When you describe quality, strategy, and so on, it is usually positive. Positive usage examples:
When used directly on a person, it is usually negative. If you say a person considering himself as "高人一等"， you don't like him because you think he is arrogant and always see below others. Please note that, the general idea is that you should NOT 高人一等, so if you say "我觉得他高人一等"，that is not a praise, that is the same as "I feel he is arrogant and not friendly".
Negative usage examples:
It is a common phrase, not an idiom. 人 here doesn't actually mean 'people', but more like 'others'
高一等 = higher by one rank/ class
高人一等 = higher than others by one rank/ class = supreme/ superior
This expression is usually used for non-human subjects. For example 品質高人一等，地位高人一等，實用性高人一等 (Superior quality, superior status, superior practicability)