In Spanish slang, 'chiflar' can mean to whistle, but it is also used colloquially to express disapproval or rejection, similar to 'to boo' in English. In some regions, it can also mean to ignore someone.
Examples
- Spanish: Cuando el artista empezó a cantar fuera de tono, la gente comenzó a chiflar.
- English: When the artist started to sing off-key, people began to boo.