The Vietnamese word "hôi nách" refers to a specific kind of body odor that comes from the underarms. It is often associated with sweat and can be considered unpleasant.
Casual: “Hôm nay trời nóng quá, chắc mình bị hôi nách.”
(Today is so hot; I think I have body odor.)
Descriptive: “Cần phải tắm rửa thường xuyên để không bị hôi nách.”
(You need to shower regularly to avoid body odor.)