Erstwhile and Then

Erstwhile adjective - Having been such at some previous time.

Then and erstwhile are semantically related. in former topic. In some cases you can use "Then" instead the word "Erstwhile" as an adjective or an adverb.

Then adjective - At a specific prior time.

Erstwhile and then are semantically related. You can use "Erstwhile" instead the word "Then" as an adjective or an adverb.