"Offset" is design feature in golf clubs that originated in game-improvement clubs
and is now found in many irons and some woods and hybrids. When the leading edge
of a clubface
is set back from the hosel
or neck - creating the image at address as seen in the photo to the right - the club is said to have "offset." Another way of saying it is that the shaft appears to be in front of the clubface (because it is).
Offset originated in putters to help golfers get their hands ahead of the ball at impact. Offset irons and woods can be helpful to golfers who slice because they provide just a split-second more time to get the clubface square before impact.
The amount of offset varies depending on the target audience for the clubs in question, from none in clubs intended for better players, to 3/8-inch or even a quarter inch in super-game improvement clubs targeted at high handicappers who slice.
For more discussion of offset, see the FAQs:
What is offset?
Will offset clubs help my slice?
Charlie buys clubs with a lot of offset to help with his slicing problem.