off (one's) chump

off (one's) chump

Crazy or insane. He must be off his chump to pay that much money for that old car. Am I completely off my chump for starting a business in this economy?
See also: chump, off
Farlex Dictionary of Idioms.

off your chump

crazy. British informal
The literal sense of chump meaning ‘a broad, thick block of wood’ led in the mid 19th century to its humorous use to mean ‘head’, with the implication of ‘blockhead’.
See also: chump, off
Farlex Partner Idioms Dictionary

off one’s chump

mod. crazy; nuts. Am I off my chump, or did that car suddenly disappear?
See also: chump, off
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • off one’s chump
  • off your chump
  • be off (one's) chump
  • chump
  • (I've) got to take off
  • be off for (something)
  • be off for sth
  • (Now) where was I?
  • be off (one's) rocker
  • be well off for something