Definition of m' in English:

m'

possessive determiner

British
  • ‘he can't hold the Bible, m'lud’
    short for my (representing the pronunciation used by lawyers in court to refer to or address the judge or a fellow barrister on the same side)
    • ‘I will never leave you M'dear.’
    • ‘Have some Madeira, m'Dear!’
    • ‘Socks are another area where negative ease can be a good thing (better to fit into your shoes, m'dear).’

Pronunciation:

m'

/mə/