IPA: /ˈhɑːbərər/
KK: /ˈhɑrbərər/
A person who provides shelter or refuge to someone, often in a secretive or illegal manner.
The harborer of the fugitive was arrested by the police.
Harborer → It is formed from "harbor" (from Old English *herebeorg*, meaning a shelter or refuge) and "-er" (meaning a person who). A harborer is a person who provides shelter or refuge.
Think of someone who provides a 'shelter' ('harbor') — the '-er' indicates that this person is the one giving that shelter.