A person who confides or tells secrets and private thoughts to someone else.
From confide (Latin confidere, 'to trust together') + -er agent suffix. The root comes from com- (together) + fidere (to trust), literally 'trust together.'
The word confider is rare in modern English because we usually just say someone 'confides in' someone else, but it perfectly captures the idea that confiding is an action one person performs—it's surprisingly specific.
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