Translation guide
A male horse, especially one kept for breeding. In Japanese, the most common word is 種馬, but other terms exist depending on context.
stallion (breeding)
stallion (general male horse)
The most common meaning: a male horse used for breeding purposes.
Referring to any adult male horse, not necessarily for breeding.
General term for a male horse. Can be used for any adult male horse, but less specific than 種馬.
That male horse has a very wild temperament.
Another general term for a male horse, often used in written or formal contexts. Can be ambiguous with 種牡馬.
Informal, often humorous reference to a sexually potent man.
In slang, 種馬 can refer to a virile man, similar to English 'stallion'. This is informal and may be considered crude.
This usage is very informal and can be offensive. Use only in casual, familiar settings.
He thinks he's a stallion.
種馬 specifically means a stallion used for breeding. 雄馬 is a general term for any male horse. 牡馬 is also a general term but is more formal/written. In everyday speech, 雄馬 is most common for a male horse, while 種馬 is used when breeding is relevant.
In English, 'stallion' often implies an uncastrated male horse. In Japanese, 雄馬 simply means male horse and does not specify castration status. To be precise about an uncastrated male, you may need to say 去勢していない雄馬 (castrated not male horse).
This stallion has won many graded stakes races.
Stallions and mares have different physiques.