IPA: /ˌʌn.rɪˈtaɪər/
KK: /ʌnˈrɪtaɪər/
To go back to work after having previously retired.
After a year of traveling, she decided to unretire and return to her job.
Past: unretired
Past Participle: unretired
Unretire → It is formed from "un-" (meaning not or opposite of) and "retire" (from Latin "retirare", meaning to draw back or withdraw). The word "unretire" means to not withdraw or to come back from retirement.
Think of 'not withdrawing' ('un-') from a previous state of 'withdrawing' ('retire') — that's why unretire means to come back from retirement.