Vocabulary What does 酸っぱい (すっぱい, suppai) mean? 酸っぱい (すっぱい, suppai) means sour; acid. Quick factsReadingすっぱいRomajisuppaiPart of speechi-adjective 酸っぱいすっぱいsuppaisour; acid1i-adjective sour; acidKanji in this word酸acid; sour; bitter, sorrowful