ころっとsound of something small rolling once (often into a hole), easily, suddenly, completely (e.g. forgetting), utterly, disappointing, curling up into the fetal position, going to sleep suddenly

風(かぜ)で野球(やきゅう)ボールがコロッと転(ころ)がった。

The baseball rolled easily in the wind. {sound of something small rolling once (often into a hole), easily, suddenly, completely (e.g. forgetting), utterly, disappointing, curling up into the fetal position, going to sleep suddenly}

言(い)うことをコロッと変(か)える人(ひと)は信用(しんよう)出来(でき)ない。

One cannot trust a person who suddenly and completely changes what they say. {sound of something small rolling once (often into a hole), easily, suddenly, completely (e.g. forgetting), utterly, disappointing, curling up into the fetal position, going to sleep suddenly}

認知(にんち)症(しょう)になって大事(だいじ)なことをコロッと忘(わす)れるようになった。

I developed dementia and began to completely forget important things, as easily as a small object rolling into a hole. {sound of something small rolling once (often into a hole), easily, suddenly, completely (e.g. forgetting), utterly, disappointing, curling up into the fetal position, going to sleep suddenly}

まさか世界(せかい)王者(おうじゃ)がコロッと負(ま)けてしまうとは思(おも)っていなかった。

I never thought that the world champion would lose so easily and completely. {sound of something small rolling once (often into a hole), easily, suddenly, completely (e.g. forgetting), utterly, disappointing, curling up into the fetal position, going to sleep suddenly}

よほど疲(つか)れていたみたいで、ベッドに入(はい)ったらコロッと寝(ね)てしまった。

It seems like I was extremely tired, as I fell asleep instantly once I got into bed. {sound of something small rolling once (often into a hole), easily, suddenly, completely (e.g. forgetting), utterly, disappointing, curling up into the fetal position, going to sleep suddenly}