one-off

adjective

1. done, occurring, or made only once; one-shot.

noun

2. something occurring, done, or made only once.

noun

1. British
   1. something that is carried out or made only once
   2. (as modifier)a one-off job

   Also: one-shot

n.“single example of a manufactured product,” 1934, from one + off. Later given figurative extension.