firecracker n. + Add to list US //ˈfaɪɝˌkɹækɝ// UK //fˈaɪəkɹækɐ// fire·crack·er Slang SynonymsEtymology Synonyms bangercrackerOrigin From fire + cracker. Idioms1 entry01wet firecrackerA person, event, or object lacking liveliness or failing to generate excitement, especially when there was a prior expectation of liveliness or excitement.