caffeine caffeina • caffeinic · · · Info · Definitions · Synonyms · Characters · · caffeine · · Text Latin · · Script 8 · · Length Definitions · · · (noun) a bitter alkaloid found in coffee and tea that is responsible for their stimulating effects. Synonyms: caffein. · · Noun Definition 1 Synonyms · · · caffein · · Synonym 1 Characters · · a latin small letter a U+0061 c latin small letter c U+0063 e latin small letter e U+0065 f latin small letter f U+0066 i latin small letter i U+0069 n latin small letter n U+006E