そんな失礼なことは言うものではない

N4 そんな sonna such, that kind of, so N4 失礼 shitsurei impoliteness, discourtesy, excuse me N5 では dewa then, well, in that case

N3 失 shitsu / ushina.u, u.seru lose, error, fault N3 礼 rei, rai salute, bow, ceremony N4 言 gen, gon / i.u, koto say, word, dire

N3 〜ものではない mono de wa nai Indicates negative advice or moral rule, attaches to a verb, means one should not do N4 〜ので node Indicates cause or reason in a softer way than kara, connects two clauses, often used in polite explanations N5 〜で de Indicates where an action happens, means used, tool, cause, or material depending on context N5 〜と to Indicates company, quotation, natural condition, complete list, or direct connection between elements N5 〜の no Indicates possession, relation between nouns, nominal explanation, or turns a verb into a noun phrase N5 〜も mo Means also, adds another similar item, often replaces particles such as wa ga or o N5 〜は wa Marks the topic of the sentence, indicates what the sentence is about, can contrast with another element, organizes main information