まあまあ

まあまあ
adverb
so-so; fairly; passably
emotion
1. so-so; fairly; passably
Neither good nor bad; average or acceptable.
まあまあ美味(おい)しい
It's fairly delicious.
調子(ちょうし)?ーまあまあだ
How are you doing? —So-so.
The results of this exam were so-so.
2. now, now; calm down
Used to soothe or calm someone.
まあまあ、()()いて
Now, now, calm down.
Now, now, don't get so angry.
まあまあ、(はなし)()いてからにしましょう。
Now, now, let's hear what they have to say first.

まあまあ is a versatile expression with two distinct uses.

Sense 1 - so-so / fairly

Indicates something is average or acceptable — not bad, but not great either. Often implies 'better than expected but nothing special.'

SENSE 2 - NOW, NOW / CALM DOWN:
Used to soothe or placate someone who is upset or agitated. Often followed by a suggestion or reassurance.

Register

Casual and conversational. Both senses are common in everyday speech. The soothing sense is often used by older speakers or in a gently patronizing way.