noun, noun or participle which takes 'suru', intransitive verb
crying loudly; wailing; bawling
Describes audible, intense crying, often in public or emotional situations. The standard meaning.
彼女は悲しい映画を見て号泣した。
She cried loudly watching a sad movie.
サッカーの試合に負けて、選手たちは号泣していた。
After losing the soccer match, the players were wailing.
noun, noun or participle which takes 'suru', intransitive verb
crying one's eyes out; weeping copiously
Colloquial, non-standard usage emphasizing the volume of tears rather than the sound. Often implies crying without making noise, but the core is extreme tearfulness.
彼に振られて、トイレで号泣した。
After he dumped me, I cried my eyes out in the bathroom.