kachi-kachi
Something that has become extremely hard — frozen ground, stale bread, or tense muscles.
💡Forgetting ice cream in the freezer — 'It's kachi-kachi, I can't scoop it.'
アイスがかちかちに凍っている。
The ice cream is frozen kachi-kachi.
The ground was ___ frozen this morning.
今朝は地面が○○に凍っていた。