Mainstream rappers often use a tried and tested formula that resonates with the general public. They would often use pop elements and techniques that their audience is already familiar with. However, some like to experiment and develop weird but signature styles.
Being called “unorthodox” in rap means that your artistry is different, unique, or even weird. You might be experimenting or just making what you feel is great. Several indie rappers are unorthodox and often create unique works. Here is how to use this term:
“I bet Jay-Z’s style was called “unorthodox” before he made it popular.”
“Most SoundCloud rappers do some weird and unorthodox stuff to their songs.”