Definition of show one's teeth in English:

show one's teeth

phrase

British
  • Demonstrate or use one's power or authority in an aggressive or intimidating way.

    ‘the council showed its teeth for the first time by imposing an economic embargo’
    • ‘Chances were few and far between in the early stages and Clydebank were the first to show their teeth when Tony McPeak headed a cross from Eric Paton only to see it blocked by a defender.’
    • ‘West Ham had by no means blown themselves out, but early in the second half Albion showed their teeth.’
    • ‘She said that the agency ‘would show its teeth to bring that attitude to a swift end’.’