It seemed a relief to the pent-up feelings to sing at the top of the voice.
Mercy had heard all, and her pent-up grief broke out in sobs.
Then, left alone with her pent-up emotions, she no longer resisted them.
He smiled knowingly at her, and Marion loosed some of her pent-up laughter.
He would like to have had a few at that moment as a relief to his pent-up emotions.