To preach to someone repeatedly or excessively; to preach at length.
From 'be-' intensifying 'preach,' from Old French 'precher' via Latin 'praedicare.' Means to overwhelm with preaching or sermonizing.
Parents have been 'bepreaching' their teenagers since forever—the word suggests not just one sermon but an endless barrage of moral instruction that teenagers definitely aren't paying attention to.
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