An onomatopoeic adverb expressing a heavy, weighty feeling or impact — physically (a heavy object) or emotionally (a heavy impression).
箱を床に置くと、ずしっと重みを感じた。
When I set the box on the floor, I felt a heavy weight.
彼の一言が胸にずしっと響いた。
His single remark hit me hard (left a heavy impression).
朝起きたら腰にずしっと痛みがあった。
I woke up with a heavy pain in my lower back.