nouninformal, slang North American
1(often humorous and depreciative). The action or practice of seeking out or investigating bugs; specifically searching for or collecting insects and other bugs, especially as entomological specimens.
2The action or practice (especially among homosexual men) of actively seeking infection with the HIV virus through unprotected sex with HIV-positive partners.
Late 19th century; earliest use found in Scientific American. From bug + chasing.