It took me a long time to realize that one character often doesn’t stand for a single English word in Chinese. As I’ve learned more Mandarin I’ve come to discover that there are a lot of people walking around with nonsensical single-character tattoos. Context matters in characters.
With that said, why 正？
First, it’s a beautiful, blocky character. It’s a little foreign, a little exotic. But it’s still accessible. You could draw it it you tried.
By itself you might translate it as “positive.” Coupled with a second character it implies realness and maybe a little urgency:
正在: right now. It’s going on right now.
六点正: it’s six o’clock right now.
正边：The front side of something.
Chinese speakers please weigh in. My Mandarin is terrible.