one-way

Allowing movement, vision, etc. in only one direction; unidirectional.

one-way mirror

The town centre is now a system of one-way streets.

Allowing travel in only one direction.

I bought a one-way ticket to Leeds.

Of a function: easy to compute for every input, but hard to invert given the image of a random input.

To use a disc harrow to turn the soil and kill weeds, in preparation for planting seeds.

Over a period of 10 years, the average yield under stubble-mulch tillage has been 10 percent greater than under one-waying with continuous wheat, and 14 percent greater than under one-waying with wheat on fallow.