be the exception that proves the rule

be the exception that proves the rule

To contradict a rule and thus confirm that the rule exists. A: "We're always told to get eight hours of sleep, but I usually feel really groggy when I sleep that much." B: "Well, I guess you're the exception that proves the rule."
See also: exception, prove, rule, that
Farlex Dictionary of Idioms.
See also:
  • exception
  • (I've) got to go home and get my beauty sleep
  • rule with a velvet glove
  • rule the school
  • a rule of thumb
  • rule of thumb
  • abide
  • abide by
  • make an exception
  • rule the roost