at someone's expense
US /æt ˈsʌm.wʌnz ɪkˈspɛns/
UK /æt ˈsʌm.wʌnz ɪkˈspɛns/

1.
atas perbelanjaan seseorang, dengan mengorbankan seseorang
paid for by someone; causing loss or damage to someone
:
•
The company party was held at the company's expense.
Parti syarikat diadakan atas perbelanjaan syarikat.
•
He made a joke at her expense, which made her feel uncomfortable.
Dia membuat jenaka atas perbelanjaannya, yang membuat dia berasa tidak selesa.