NUT - A hard-shelled seed.
PIN - A small device, made (usually) of drawn-out steel wire with one end sharpened and the other flattened or rounded into a head, used for fastening.
PIT - A hole in the ground.
PUT - To place something somewhere.
RIP - A tear (in paper, etc.).
RUN - Act or instance of running, of moving rapidly using the feet.
RUT - Sexual desire or oestrus of cattle, and various other mammals.
TIN - A malleable, ductile, metallic element, resistant to corrosion, with atomic number 50 and symbol Sn.
NIP - A small quantity of something edible or a potable liquor.
NIT - The egg of a louse.
PINT - A unit of volume, equivalent to 1/8 of a gallon or 16 ounces.
PUNT - A pontoon; a narrow shallow boat propelled by a pole.
RUIN - Construction withered by time.
TRIP - A journey.
TURN - Of a body, person, etc, to move around an axis through itself.
UNIT - A standard measure of a quantity.
RUNT - The smallest animal of a litter.
INPUT - The act or process of putting in; infusion.
PRINT - Of, relating to, or writing for printed publications.
TURNIP - The white root of a yellow-flowered plant, Brassica rapa, grown as a vegetable and as fodder for cattle.