Definitions

1. adverb

in the past, at a previous time; formerly, at some time in the past

“He was a king whilom, but now he’s just a humble farmer.”

2. noun

a former or past person or thing; something that existed or happened in the past

“The whilom palace was now a museum.”

3. adjective

of or relating to a past time; former, past

“The whilom friendship has been forgotten over time.”