noun
restive horse; unruly horse
Literal meaning: a horse that is difficult to control, often bucking or refusing commands.
あのじゃじゃ馬はなかなか言うことを聞かない。
That restive horse won't do what it's told.
noun
unmanageable person; shrew; stubborn tomboy
Idiomatic use, especially for a strong-willed, unruly woman or girl. Often carries a slightly humorous or affectionate tone.
She's been a tomboy since she was little, often getting into fights with boys.
うちの妹は本当にじゃじゃ馬で、誰も手がつけられない。
My younger sister is a real shrew; nobody can handle her.