IPA: /ˈsoʊdʒɜrnər/
KK: /ˈsoʊdʒɜrnər/
A person who stays in a place for a short time before moving on.
During her travels, she met a sojourner who shared stories of his adventures.
Sojourner is formed from "sojourn" (from Old French *sojorner*, meaning to stay or reside temporarily) and the suffix "-er" (meaning a person who). A sojourner is a person who stays temporarily in a place.
Think of someone who 'stays temporarily' ('sojourn') in a place — the '-er' just means a person. A sojourner is someone who resides for a while.