The first use of harebrained dates to 1548. The spelling hairbrained also has a long history, going back to the 1500s when hair was a variant spelling of hare. The hair variant was preserved in Scotland into the 18th century, and as a result it is impossible to tell exactly when people began writing hairbrained in the belief that the word means "having a hair-sized brain" rather than "with no more sense than a hare." www.answers.com/topic/harebrained
easy to say that hairbrained is wrong. But even a quick look at the historical evidence stops one. The first example in the Oxford English Dictionary is dated 1548, and that has hare. But the second is from 1581, and that has hair. The editor who compiled the OED entry seems to have deliberately alternated examples in the two forms, since there’s roughly one of each cited from every century since. www.worldwidewords.org/qa/qa-hai1.htm
-22.214.171.124 17:56, 22 March 2012 (UTC)
- Nobody necessarily doubts that it was an accepted spelling in the 16th century. The point is whether it is standard today. It is rather common apparently: "harebrained" is only about four times as common as "hair-brained", according to Ngrams.