IPA: /wɪðˈhoʊldər/
KK: /wɪðˈhoʊldər/
A person or thing that keeps something back or does not give it to someone else.
The withholder of the information refused to share it with the team.
Withholder → It is formed from "with" (from Old English "wiþ", meaning against or in opposition) and "hold" (from Old English "healdan", meaning to keep or maintain) and "-er" (meaning a person who). A withholder is a person who keeps something back or does not give it.
Think of someone who is 'keeping back' ('hold') something 'against' ('with') another — that's why a withholder is someone who withholds.