godan verb (-u), transitive verb
Often used in set phrases like 物言う目 (expressive eyes) or 物言う態度 (an attitude that speaks volumes), where something non-verbal conveys meaning. Can also mean simply 'to talk' in a slightly literary or emphatic way.
彼の目は物言うように輝いていた。
His eyes shone as if they were speaking.
沈黙
Silence can sometimes carry meaning.