rapidity rapid • rapidly · · · Info · Definitions · Synonyms · Characters · · rapidity · · Text Latin · · Script 8 · · Length Definitions · · · (noun) a rate that is rapid. Synonyms: celerity, quickness, rapidness, speediness. · · Noun Definition 1 Synonyms · · · celerity · · Synonym 1 quickness · · Synonym 2 rapidness · · Synonym 3 speediness · · Synonym 4 Characters · · a latin small letter a U+0061 d latin small letter d U+0064 i latin small letter i U+0069 p latin small letter p U+0070 r latin small letter r U+0072 t latin small letter t U+0074 y latin small letter y U+0079