狗屁 is a vulgar noun meaning 'bullshit' or 'nonsense', used to express strong contempt or rejection of someone's words, ideas, or actions. It often appears in the set phrase 放狗屁 ('to talk bullshit'). This word is very coarse and should be avoided in polite or formal contexts — learners may encounter it in casual conversation, media, or fiction, but using it yourself can sound aggressive.