まあまあ

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.'

• As a modifier: まあまあ美味(おい)しい (fairly delicious)
• As a standalone response: 調子(ちょうし)は？ — まあまあ。 (How are things? — So-so.)
• As a predicate: 結果(けっか)はまあまあだった (the result was so-so)

SENSE 2 - NOW, NOW / CALM DOWN:

Used to soothe or placate someone who is upset or agitated. Often followed by a suggestion or reassurance.

• まあまあ、落(お)ち着(つ)いて (now, now, calm down)
• まあまあ、そう言(い)わないで (come now, don't say that)

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.