irritant irritancy • irritate · · · Info · Definitions · Synonyms · Characters · · irritant · · Text Latin · · Script 8 · · Length Definitions · · · (noun) something that causes irritation and annoyance. Synonyms: thorn. Example: "He's a thorn in my flesh." · · Noun Definition 1 Synonyms · · · thorn · · Synonym 1 Characters · · a latin small letter a U+0061 i latin small letter i U+0069 n latin small letter n U+006E r latin small letter r U+0072 t latin small letter t U+0074