RhymeZone: whilom definitions

Definitions of whilom:

adverb: (archaic except literary) At some time in the past; formerly, once upon a time.
adverb: At times, on occasion, sometimes.
adverb: (rare) Preceded by of or this: for some time that has passed.
adjective: (archaic except literary) At some time in the past; former, sometime.
adjective: (obsolete) Of a person: deceased, late.

(Definitions from Wiktionary)