IPA: /ˈloʊnər/
KK: /ˈloʊnər/
A person or thing that lends something, often used as a temporary replacement for something that is being repaired.
The car rental company provided a loaner while my vehicle was in the shop.
Loaner → It is formed from "loan" (from Old English *lǣnan*, meaning to lend) and "-er" (meaning a person who). A loaner is a person who lends something to others.
Think of someone who 'lends' ('loan') something — the '-er' just means a person. A loaner is someone who lends things.