noun which may take the genitive case particle 'no', adverb, adverb taking the 'to' particle
bubbly; foamy; frothy
Mimetic word describing something full of bubbles or foam, often used colloquially. Can function as a no-adjective, adverb, or with と.
あわあわのビールが飲みたい。
I want to drink a bubbly beer.
洗剤を入れたら、水があわあわになった。
When I added detergent, the water became foamy.
泡 is the noun for 'bubble' or 'foam'; あわあわ is the mimetic adjectival/adverbial form emphasizing the bubbly state.
Reduplication of 泡 (あわ, 'bubble'), forming a mimetic word. The exact historical derivation is straightforward.