IPA: /rɪˈfrɛʃər/
KK: /rɪˈfrɛʃər/
A person or thing that refreshes, often referring to a drink or a course that helps someone review or update their knowledge.
After a long day at work, I enjoyed a cold refresher to cool down.
Refresher → It is formed from "re-" (meaning again) and "fresh" (from Old English *fresc*, meaning new or invigorating) and the suffix "-er" (meaning a person who). The word "refresher" refers to a person or thing that makes something fresh again or revitalizes it.
Think of 'again' ('re-') making something 'new' ('fresh') — that's why a refresher is something that brings back freshness.