Synonyms of erstwhile

1 Syllable
ex, past, late, old, once
2 Syllables
former, quondam, oncer, whilom, time-worn, cast-off, previous, olden, exer, castoff
3 Syllables
formerly, hitherto, preceding, preexistent, demode, prevenient, bygone, one-shot, one-time, prodromal, previously
4 Syllables
erewhile, sometime, aforeknown, forerunning, onetime
5 Syllables
above-named
6 Syllables
aforementioned, above-mentioned, abovementioned