- An iron (formerly wooden) golf club, originally one with a relatively short face and subsequently applied to most lofted irons with a heavy head, used especially for playing out of bunkers and rough ground. (Equivalent to a modern number 8 iron, 9 iron, or wedge.)
It's origin is uncertain the OED said it could come from nib, since the clubs has a hooked appearance. For another theory, it cites David Langdon's 1975 book of golf terms, How to Talk Golf: "Niblick, old fashioned term for a No. 9 iron. Said to be a corruption of Scottish ‘neb laigh’, a broken nose, referring to the short club-face."