IPA: /rɪˈtaɪərɪŋ/
KK: /rɪˈtaɪərɪŋ/
Someone who is shy and prefers to keep to themselves rather than being outgoing or social.
She is a retiring person who enjoys spending time alone with her books.
Retiring is formed from "re-" (meaning again or back) and "tire" (from Old French *tirer*, meaning to draw or pull). The word describes the act of withdrawing or pulling back, often from work or active life.
Think of someone 'pulling back' ('tire') from their duties 'again' ('re-') — that's why retiring means stepping back from work.