Definition of strewth in English:

strewth

(also struth)

exclamation

British
informal
  • Used to express surprise or dismay.

    • ‘Forget ‘strewth ‘and ‘fuller than a seaside dunny on Boxing Day‘.’
    • ‘The newspapers in Australia use slang words and phrases like ‘strewth’ and ‘that's a crock’ in their editorials.’
    • ‘He's maybe just gone down the wrong road, and, God strewth, we've all done that from time to time.’

Origin

Late 19th century: contraction of God's truth.

Pronunciation

strewth

/struːθ/