Off Your Rocker

Etymology:

• This expression has been used since the middle of 19th century. The word “rocker” is used to express the rocking chair. The meaning of this idiom can be considered from two different stories. First is the case that if you fell from a rocking chair it would indicate that you are mentally unstable. The second theory is based on the fact that “rockers” are the curved pieces which are used for rocking effects in chair. In case the rockers are not working properly, the whole chair will behave in a strange way. The analogy can be made to a person whose thinking is strange.