Definition of not all there in US English:

not all there

phrase

  • (of a person) not fully alert and functioning.

    ‘he's not all there—give him a couple of days to readjust’
    • ‘Granted, she's not all there, but it's part of the charm.’
    • ‘It was sobering to walk through those halls, and meet up with people who you knew were definitely not all there.’
    • ‘It's his way of telling me he understands that I'm not all there with my constant habit of spacing out.’
    • ‘I'd like to know what you meant, but I'm not all there, I guess.’
    • ‘J.T. looked up from the table, obviously not all there, and said, ‘What makes you say that, man?’’
    • ‘On those days you feel you're not all there, your mind's tempted to wander, it's hard to keep focusing.’