Differences between "bitter," "acrimonious" and "astringent." Why isn't it appropriate to describe an argument as "astringent"?

Question

>After having ___ arguments virtually every other day,the couple agreed that it was best for them to separate.>A) bitter>B) saturnine>C) astringent>D) effulgent>E) acrimonious>F) assiduousThis is a GRE sentence completion question, Type: Sentence Equivalence, which means that two most suitable options for the sentence are to be selected from the given options. So, basically the selected words will be synonyms of each other.Here, I am confused about 'bitter', 'astringent', and 'acrimonious' because these are synonyms of each other. And my book has 'bitter' and 'acrimonious' as the answer. Why not 'astringent'?

Answer 1

In astringent's definition, bitter refers to smell or taste. The definitions of bitter and acrimonious, however, refer to feelings of anger. Words can have varying shades of meaning outside of the test, but when taking the GRE, I have found it best to rely on the exact definitions of the words.