1. Bostin(g) is a well-known word meaning amazing, brilliant or excellent. The g is rarely written or pronounced. Bost is (like the similar word bust) slang for broken, and so the word bostin' means the same as 'smashing.'
This brought back memories. The first time I heard this word was when the Birmingham band We've Got A Fuzzbox and We're Gonna Use It!! (later shortened to plain "Fuzzbox") brought out their first album "Bostin' Steve Austin".