Hairbrained \Hair"brained`\ (h[^a]r"br[=a]nd`), a. See {Harebrained}. Hairbreadth
Harebrained \Hare"brained`\ (h[^a]r"br[=a]nd`), a. Wild; giddy; volatile; heedless. "A mad hare-brained fellow." --North (Plutarch). [Written also {hairbrained}.] [1913 Webster]