Definition of bosting in English:

bosting

(also bostin)

adjective

Midlands English
  • Very good; excellent.

    ‘have a bostin time if you are celebrating Black Country Day today’
    ‘the fish and chips were bosting’
    • ‘Regional dialects are as bostin, chuffed and made up as at any time in history, according to preliminary findings.’
    • ‘Doncaster suggested smart; Londoners buff; Midlanders bostin; and the Scots stoater.’
    • ‘We had a bostin' time.’

Origin

1970s: probably a dialect pronunciation of bursting or busting.

Pronunciation

bosting

/ˈbɒstiŋ/