"Mumble rap" refers to a style of rap music where the lyrics are often difficult to understand because of how the rapper delivers them. It's like when someone talks with their mouth full of food or when they're talking while covering their mouth.
Sometimes the words are slurred and sound like they're being mumbled, which is where the name "mumble rap" comes from. The style is popular among younger generations, and it uses a lot of repetitive beats, auto-tune effects, and catchy phrases.
While some people might not like mumble rap because they can't understand the lyrics, others enjoy the style and the way the music feels. Some critics argue that it lacks substance and creativity, but fans see it as a way to express themselves and have fun. Ultimately, like all forms of music, it's up to personal taste and preference.