That looks like the Konica AR mount. The last cameras that used this mount were produced up to 1987. I still own a Konica FS-1 camera body (made from 1979 to 1983) that I bought used in the mid-1980s just before Konica abandoned the SLR camera market.
The Konica AR mount had a flange focal distance of 40.5mm and a throat diameter of 47mm.
The Nikon F-mount has a flange focal distance of 46.5mm and a throat diameter of 44mm.
Since the Nikon flange distance is further from the sensor than the Konica, it is not possible to adapt a Konica lens to a Nikon camera without either:
- Adding additional optics to focus the light from the rear of the lens onto the sensor that is further back than that for which the lens is designed. These additional optics also have a teleconverter effect.
Or
- Accepting that the lens will only be able to focus at extremely short focus distances without additional optical elements.
Since the throat diameter is wider on the Konica mount than the Nikon mount the lens can't be allowed to protrude into the body of a Nikon camera even if the mirror clearance were not an issue.
There are commercially available adapters to use a Konica AR lens on a Nikon F-mount camera. They generally also act as 1.4x teleconverters that would make your lens act like a 50mm f/4 lens on your Nikon. You also give up camera control of the lens' aperture and automatic metering. You have to use stop-down metering to use the camera's light meter with such a lens. Additionally, your lens, as are all Konica AR mount lenses, is manual focus only.
If you already own a 50mm f/1.8 lens with autofocus and automatic aperture control it would not be worth the trouble to purchase even a cheap adapter to give you a 50mm f/4 manual focus, stop down metering lens.
If you don't already own a 50mm f/1.8 F-mount lens for your Nikon camera you can probably find one used for not much more than the price of an adapter for the Konica AR mount lens. Since your Nikon D7000 has a focus motor in the body, any 50mm D or G series lens will autofocus and auto meter with your camera.