have someone's number
US /hæv ˈsʌm.wʌnz ˈnʌm.bər/
UK /hæv ˈsʌm.wʌnz ˈnʌm.bər/

1.
누구의 속셈을 알다, 누구의 약점을 알다
to know someone's true character or intentions, especially their weaknesses or secrets
:
•
I think I have his number; he's all talk and no action.
나는 그의 속셈을 알아. 그는 말만 많고 행동은 없어.
•
The detective quickly had the suspect's number and knew he was lying.
형사는 재빨리 용의자의 속셈을 알아챘고 그가 거짓말하고 있다는 것을 알았다.