Definition of post up in US English:

post up

phrasal verb

Basketball
  • Play in a position near the basket, along the side of the key.

    • ‘If their big player posts up near the basket, have the defender play in front of the big player.’
    • ‘He lulls defenders by beginning with his back to the basket like he is posting up.’
    • ‘For example, it's difficult to stop players who post up near the basket.’
    • ‘‘I definitely feel more comfortable facing the basket than posting up,’ Brown says.’
    • ‘If someone's posting up and the defender is in the paint in the post-up position, does that count as three seconds?’