countersignature countersignal • countersink · · · Info · Definitions · Synonyms · Characters · · countersignature · · Text Latin · · Script 16 · · Length Definitions · · · (noun) a second confirming signature endorsing a document already signed. Synonyms: countersign. · · Noun Definition 1 Synonyms · · · countersign · · Synonym 1 Characters · · a latin small letter a U+0061 c latin small letter c U+0063 e latin small letter e U+0065 g latin small letter g U+0067 i latin small letter i U+0069 n latin small letter n U+006E o latin small letter o U+006F r latin small letter r U+0072 s latin small letter s U+0073 t latin small letter t U+0074 u latin small letter u U+0075