noun
clumsy girl; klutz
Otaku culture slang for a female character (or sometimes a child) who is endearingly clumsy or accident-prone. Often used affectionately in anime, manga, and light novels.
あのアニメのヒロインはドジっ子で、よく転んだり物を落としたりする。
The heroine of that anime is a clumsy girl who often trips and drops things.
妹はドジっ子だから、料理をさせるとキッチンが大変なことになる。
My little sister is such a klutz that the kitchen becomes a disaster when she cooks.
ドジ is a noun or na-adjective meaning 'blunder' or 'clumsy mistake.' ドジっ子 is a derived character type that personifies that clumsiness.
天然ボケ refers to a person who is naturally airheaded or says funny things unintentionally. ドジっ子 focuses more on physical clumsiness and is strongly associated with otaku character archetypes.
Derived from ドジ (blunder) + 子 (child/girl), with the diminutive っ inserted for euphony. The exact origin is uncertain, but it emerged in otaku and internet slang to describe a cute, clumsy female character archetype.