somthing awesome, amazing usually a car or a song but most often used to describe a blunt or joint . This word orginates from glasgow pollcokshields or "shieldz" area usually spoken amongst young asian glaswegian youths.
> tony- bro did u see that black range rova with the heavy wheelz
> Ali- o i dats boostah
> Tony- gna paas the joint man
> Ali- 2mins bro, this sh*t is boostah