You use erstwhile to describe someone that used to be the type of person indicated, but no longer is. He ran away with an erstwhile friend of his wife's.

What does erstwhile mean?

: in the past : formerly cultures, erstwhile unknown to each other— Robert Plank. erstwhile. adjective. Definition of erstwhile (Entry 2 of 2) : former, previous erstwhile enemies.

What is the sentence of erstwhile?

1. His erstwhile friends turned against him. 2. She found herself ostracized by erstwhile friends.