I have been given a makinon lens but it does not fit on my nikon D5000?

I have a Nikon D5000 and was given a Makinon lens. I know that I need some sort of adapter but unsure as to where I should start looking. Any help would be appreciated so that I can use this lens on my camera! Thank you

Added (1). Thanks for your help guys, bit dissapointing that i really can't do anything with it though!

Short answer: You can't.

Long answer: An adapter might be possible (what type of lens mount is the lens? Minolta? One needs to know to give you an answer), but such adapters usually come with very serious drawbacks. No autofocus, loss of one or two stops worth of light, and usually no metering either. They're just not worth the hassle, it won't be fun to use a lens that way at all.

You're best off selling that lens on craigslist and getting a proper Nikon AF-S lens instead.

There may or may not be an adapter. Makinon lenses were made in a variety of mounts, and you would have to know which one in order to adapt it. If it happens to be a screw thread, then that would be obviously probably an M42 mount, and there's an adapter available. The Nikon mount is narrower than most, so for many lenses there's no adapter to a Nikon body. It may not be worth bothering with anyway, having no autofocus, no autoexposure, and no metering with your camera. The lens could be useful as a magnifier.