erstwhile
ˈəːstwʌɪl/
adjective
adjective: erstwhile

    1.
    former.
    "the erstwhile president of the company"
    synonyms:        former, old, past, one-time, sometime, as was, ex-, late, then; More
    previous, prior, foregoing;
    formalquondam;
    archaicwhilom
    "written in memory of the composer's erstwhile teacher"
    antonyms:        present, future

adverb
archaic
adverb: erstwhile

    1.
    formerly.
    "Mary Anderson, erstwhile the queen of America's stage"

Simple really!