noun
long speech; monologue
Refers to a lengthy spoken part in a play, film, or conversation; often implies a single person talking at length.
彼の長台詞が終わるまで誰も口を挟まなかった。
No one interrupted until his long speech was over.
あの俳優は長台詞を完璧に覚えていた。
That actor had perfectly memorized the long monologue.
Compound of 長 (long) and 台詞 (speech, line). The reading ながぜりふ follows standard rendaku voicing of せりふ to ぜりふ in compounds.