A bad odor associated with sweating is known as bromhidrosis. It can be generalized or localized to areas like the armpits. Causes of a Bad Body Odor Foul Body Odor. Although a foul odor is a general term for any offensive smell, the odor may vary in character and intensity. It may be described by a number of terms, including musty, mousy, fishy, putrid, fetid, fecal or sickening sweet odor. The causes of foul body odor in general may be due to the following causes : Bromhidrosis (also known as ozochrotia or osmidrosis is mentioned above) Poor hygiene; Tobacco smoking; Alcohol consumption; Topical applications; Foul odor from clothing; Causes of halitosis (bad body odor) Discharge from the penis, vagina, ear, nose; Skin infections, abscess