also: まじょこ
noun
magical girl; young witch
Refers to a girl with magical powers, typically in anime, manga, or similar media. Often used for characters who transform or use magic, akin to the 'magical girl' genre. Can also simply mean a young witch.
See also: 魔法少女
このアニメの主人公は魔女っ子で、変身して悪と戦う。
The protagonist of this anime is a magical girl who transforms and fights evil.
彼女は魔女っ子のコスプレをしている。
She is cosplaying as a magical girl.
魔法少女 is the more standard term for 'magical girl' in anime/manga. 魔女っ子 has a slightly more nostalgic or retro feel, often associated with older series or a cuter, witch-like image.
Compound of 魔女 (majo, 'witch') + っ子 (-kko, diminutive suffix meaning 'child' or 'girl'). The suffix っ子 adds a cute or affectionate nuance, common in terms for young characters.