Definition of bats in English:

bats

adjective

dated, informal
  • predicative (of a person) mad.

    • ‘I think the kid and I knew she was bats but she was a hoot to be with.’
    • ‘She was bats and contrary, but she seemed to be self-aware and have a genuine sense of humour about her own battiness and contrariness.’
    • ‘We realize in short order that she's bats, and that simple observation steals a great deal of power from the proceedings.’
    • ‘I have in fact stated a number or times that I think he's bats.’
    • ‘Either that, or she was bats.’
    • ‘But he was bats and incomprehensible before he took ill.’
    • ‘I know she's good at getting press (partially because she's really good at marketing her fair-weather femininity), but it's obvious that she's bats.’
    • ‘He was bats for buying in the face of a housing downturn.’
    severely mentally ill, mentally ill, insane, mad, certifiable, deranged, demented, of unsound mind, out of one's mind, not in one's right mind, not together, crazed, maniac, maniacal, lunatic, unbalanced, unhinged, unstable, disturbed, distracted, stark mad, manic, frenzied, raving, distraught, frantic, hysterical, delirious, mad as a hatter, mad as a march hare
    View synonyms

Origin

Early 20th century: from the phrase have bats in the belfry (see bat).

Pronunciation

bats

/bats/