off one's rocker

noun

1. Also called runner. one of the curved pieces on which a cradle or a rocking chair rocks.
2. rocking chair.
3. a performer or fan of rock-‘n’-roll. music.
4. a rock-‘n’-roll song: She sang a ballad and followed that with two of her well-known rockers.
5. any of various devices that operate with a rocking motion.
6. Graphic Arts. a small steel plate with one curved and toothed edge for roughening a copperplate to make a mezzotint.
7. Mining. cradle(def 13).
8. an ice skate that has a curved blade.

Idioms

9. off one’s rocker, Slang. insane; crazy: You’re off your rocker if you think I’m going to climb that mountain.

noun

1. any of various devices that transmit or operate with a rocking motionSee also rocker arm
2. another word for rocking chair
3. either of two curved supports on the legs of a chair or other article of furniture on which it may rock
4. a steel tool with a curved toothed cage, used to roughen the copper plate in engraving a mezzotint
5. mining another word for cradle (def. 9)
6. 1. an ice skate with a curved blade
   2. the curve itself
7. skating
   1. a figure consisting of three interconnecting circles
   2. a half turn in which the skater turns through 180°, so facing about while continuing to move in the same direction
8. a rock-music performer, fan, or song
9. British an adherent of a youth movement rooted in the 1950s, characterized by motorcycle trappingsCompare mod 1
10. off one’s rocker slang crazy; demented

n.“a rocking chair,” 1852, American English, from rock (v.1); earlier “nurse charged with rocking a cradle” (early 14c.). In sense of “one of the curved pieces of wood that makes a chair or cradle rock” it dates from 1787. Slang off (one’s) rocker “crazy” first recorded 1897. Meaning “one who enjoys rock music” (as opposed to mod (n.1)) is recorded from 1963, from rock (v.2). Also, off one’s nut or trolley. See off one’s head. see off one’s head (rocker).