Hilman, THO is a misspelling of THOUGH used in slang - especially in the expression "that xxx tho" which means something like "Oh my God, look at that xxx!" For instance, let's say you and your friends are sitting in the park and a gorgeous girl walks by. One friend says "Wow, look at her!" Your other friend jokingly says "Don't talk like that about my girlfriend!" and you can say "That body tho!"

It's always good to provide an example, for context, but "tho" is likely a short form of "though" or "although."