Definition of (as) thick as thieves in US English:

(as) thick as thieves

phrase

informal
  • (of two or more people) very close or friendly; sharing secrets.

    • ‘I can't remember how our friendship really got going, but before we knew it we were thick as thieves.’
    • ‘The younger girl is drawn to Anita's rebellious streak and they soon become thick as thieves.’
    • ‘In the olden days, Bryan and Justin had been as thick as thieves, closer than brothers, best friends for life.’
    • ‘‘By the end, we were all thick as thieves,’ insists McCann.’
    • ‘We were as thick as thieves and would share any secret with one another.’
    • ‘No wonder she and Claire were the best of friends and thick as thieves.’
    • ‘‘He was seven years older than I, but even then, we were inseparable, thick as thieves,’ she said with a soft laugh.’
    • ‘They lost interest in each other during the teenage years - by then it was all about rivalry - but now, as mothers themselves, they're as thick as thieves again.’
    • ‘I was in love with her, and for two years the two of us were thick as thieves.’
    • ‘Besides, I thought you two were as thick as thieves.’
    friendly, intimate, familiar, on friendly terms, on good terms, on the best of terms, hand in glove
    View synonyms