noun
sexually transmitted disease; STD; venereal disease
Medical and everyday term for infections spread through sexual contact. 性感染症 (せいかんせんしょう) is a more modern clinical term, but 性病 remains common.
性病の予防にはコンドームが有効です。
Condoms are effective for preventing STDs.
彼は性病
He got tested for sexually transmitted diseases.