Translation guide
A horse that has not been tamed or trained for riding or work.
Describing a horse that has never been domesticated or trained.
Referring to a domestic horse that has not been trained to accept a rider or harness.
A descriptive phrase meaning 'a horse that has not yet been trained'. This is the clearest way to express the concept in Japanese.
The English phrase 'unbroken horse' does not have a single-word equivalent in Japanese. Using a direct translation like 壊れていない馬 would mean 'a horse that is not broken (physically)' and would be incorrect.
I saw a herd of wild horses galloping across the plain.
This horse hasn't been broken in yet, so it's dangerous to ride.
Literally 'rough horse', often used for a horse that is wild, unruly, or not fully tamed. Can also imply a spirited or difficult horse.
He is good at taming unbroken horses.
Means 'a horse that has not been tamed/gentled'. Less common than 調教されていない馬, but still understandable.
It's dangerous to approach an unbroken horse.