Erstwhile and One-shot

Erstwhile adverb - At an earlier or previous time.

One-shot and erstwhile are semantically related In some cases you can use "One-shot" instead an adverb "Erstwhile".

One-shot adjective - Happening only once.

Erstwhile and one-shot are semantically related in earlier topic. You can use "Erstwhile" instead an adverb phrase "One-shot".