have someone's number

have (got) (one's) number

To understand or know someone or something well enough to anticipate what they will do. That team is impossible to beat—they've had our number since 2006! Oh, don't worry, I've got his number—he's a typical brat.
See also: have, number
Farlex Dictionary of Idioms.

have someone's number

If you have someone's number, you understand what kind of person they are, and so you know how to deal with them. Oh, don't worry — I won't let him cheat me. I've got his number.
See also: have, number
Collins COBUILD Idioms Dictionary, 3rd ed.

have someone's number

understand a person's real motives or character and thereby gain some advantage. informal
See also: have, number
Farlex Partner Idioms Dictionary
See also:
  • have (got) (one's) number
  • have somebody's number
  • reckon without
  • reckon without (someone or something)
  • words right out of one's mouth, to take
  • outguess (someone or something)
  • reckon on
  • reckon on (someone or something)
  • expect (someone or something) for (something)
  • expect for