Also, on the bum or fritz. Malfunctioning, out of order, broken, as in The TV is on the blink again, or You drive—our car's on the bum. The first of these slangy expressions dates from the late 1800s and possibly alludes to an electric light that flickers on and off (“blinks”); the second, from the same period, possibly is derived from bum in the sense of “a contemptible person”; the third, fritz, dating from about 1900, is of unknown origin.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.