woo woo · noun, adjective1
Uncertain. It has been suggested that "woo woo" is intended to imitate the eerie background music of sci-fi/horror films and television shows. A connection has also been suggested to stereotypical sounds of ghosts (see boo and compare goetia).
woo woo · noun2
Unknown.
woo woo · noun3
Imitative of a siren.
Etymology from Wiktionary, CC BY-SA 4.0.