Meaning of そうでもない

Question

In this sentence:

神野{じんの}菜生子{なおこ}さして意外そうでもなくうなずいた

I'm having some issue in understanding そうでもない, and according to how I read it it reverse the meaning of the sentence: as far as I understand, そうでもない means "not really", so the sentence would mean something like "Not very/really unexpectedly, Jinno Naoko nodded", but I'm not sure about そうでもない and I can't find it on my grammars.

Answer 1

Your translation seems okay. To break it down:

• 意外だ: "is unexpected"
• 意外そうだ: "looks unexpected"
• 意外そうではない: "does not look unexpected"
• 意外そうではなく: (ku-form of 意外そうではない) "not looking unexpected"
• 意外そうでもなく: "not (quite) looking unexpected"
• さして意外そうでもなく: "not really looking unexpected"

For the last も, see:

• も in 「Vのもアレなんだけど」
• What is the difference between 「とは限らない」and 「とも限らない」
• Usage of も in a Specific Context

さして "(not) very/really" is an adverb used with a negative expression (i.e., negative polarity item).