I am having the hardest time wrapping my brain around "それなりの". Can you guys help me understand how this is used?

I have seen it in the middle of a sentence, as in this quote from "マイ☆ボス　マイ☆ヒーロー"

　私には補習があるので。
　相手は前代未聞に頭の悪い生徒で、
　この1週間、私もそれなりの準備と覚悟で
　臨みたいんです。

Also, just searching on Google gives me lots of examples where it just starts a sentence:

それなりの日々
それなりの理由がある
それなりの寿司

What is the indication for using this expression? Thanks in advance!

大辞泉
１ その状態のままで変わらないこと。そのまま。それきり。副詞的にも用いる。
２ いちおうそれはそれとして認められること。それ相応。

大辞林
［1］ その状態のまま。そのまま。それきり。副詞的にも用いる。
［2］ 限界や欠点はあるが、それはそうとして。それ相応に。

それなり in your examples roughly means "great, if not the greatest," "good, if not the best," "acceptable, if not (insert an adjective)," etc. It can carry either a positive or negative connotation. So sometimes it's more like "barely acceptable," etc. Sometimes it can mean "very good" and so on. The それなり in the first example (私もそれなりの準備と覚悟で...) is an example of this "very good" kind of sense.

My J-E dictionary says it means "in its own way," and I think this translation often, if not always, works. Oh, the dictionary's translation is それなりの翻訳. I think "not bad" is also a good translation, though it isn't always appropriate.

These senses of それなり always imply there is a certain limit. So it can't mean "the best of the best," but it can be from "barely acceptable" to "very good" depending on context.

Thanks guys!

Now that I am getting a better idea what it means, I wonder if I needed to include more of the original quote. In this scene, she is turning down someone who has asked her out on a date. これよく考えてみると、the "それなりの" probably relates back to the fact that she needs to do an ample amount of preparation suitable for the task at hand (which is quite large, considering the student's stupidity is unprecedented). Therefore, she probably includes it in the sense that she will not have time to go on a date (and she probably doesn't want to go out with the guy anyway).

Am I on the right track? I feel like if I'm not 100% sure why it is there, there is no way I could ever actually use the expression. Thanks again!

@danieldesu

I don't know マイ☆ボス　マイ☆ヒーロー, but reading your explanation, I think you hit the nail right on the head.