like a boss - Dictionary.com
https://www.dictionary.com/e/slang/like-a-bossBoss has long meant, and continues to mean, a “person in charge,” especially used, of course, in professional contexts. Boss has also long been a slang term for “excellent,” with evidence reaching back to the 1880s. Boss took off, though, as a youth slang term for “superlative” and the like (“That new song is boss”) in the 1960s.
Boss - What does boss mean? - The Slang Dictionary
https://slangit.com/meaning/boss06.10.2014 · Boss has 3 meanings. 1. What does boss mean? Main bad character Example "You're still on level 12?" "Yeah, this boss is so frustrating, I can't beat him!" Related Slang Usage Online Gaming Last Updated: September 30, 2015 2. What does boss mean? Awesome person Example "That guy is such a boss. He's won three tournaments in a row now."