When someone uses this term, they're basically saying they could "take you on." When someone uses this term; they mean to be highly confrontational. This term stems from video games and is used to say "I can take you on easily by myself and still beat your a*s!"
"I'll solo you"
Person 1: "how about you shut the hell up?! I could straight up solo you!
Person 2: "solo me?? You wish! I'll beat your a*s!!"
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