パンパン

• (Tokyo) ぱんぱん [pàńpáń] (Heiban – [0])
• IPA^(key): [pã̠mpã̠ɴ]

The adverb, attested from the 19th century, is onomatopoeic. The related adnominal is attested from the 20th century.[1]

パンパン or ぱんぱん • (panpan) 

1. (onomatopoeia) the sound of clapping or of striking something with one's hand
2. (onomatopoeia) bang, pow (the sound of something bursting or exploding)
   • 1994, Aihara Mariko, Shitai nōjō, translation of The Body Farm by Patricia Cornwell:

     どこかの射(しゃ)撃(げき)場(じょう)からパンパンという鋭(するど)い音(おと)が、夜(よ)明(あ)けの静(せい)寂(じゃく)を破(やぶ)って聞(き)こえてくれ。

     Dokoka no shagekijō kara panpan to iu surudoi oto ga, yoake no seijaku o yabutte kikoete kure.

     From a shooting range somewhere a sharp bang sound breaks the silence of the dawn.

パンパン or ぱんぱん • (panpan) 

1. bulging, about to burst, overstuffed

   食(た)べ過(す)ぎた。お腹(なか)がパンパンだ。

   Tabe sugita. Onaka ga panpan da.

   I ate too much. My stomach is about to burst.

Ellipsis of パンパンガール (panpangāru). This noun is attested from the 1940s.[2] Multiple theories include:

• Possibly from English pompom girl as a WW2 slang. Compare English pum-pum (“vulva”), Ilocano pampam (“prostitute”), Tagalog pampam (“prostitute”), Cebuano pampam (“prostitute”), Waray-Waray pampam (“prostitute”).
• Possibly from Indonesian perempuan (“woman”).[3]
• Possibly a semantic shift from the onomatopoeia, perhaps in reference to clapping hands to attract a prostitute

パンパン • (panpan) 

1. (slang, dated, historical) a sex worker, prostitute, especially one catering to occupying soldiers after World War II

   Synonym: パンパンガール

   • 2018, Kitagami Yūho, Sengo panpan den [Tales of post-war sex workers], volume 16, page 6:

     それでパンパンから足(あし)を洗(あら)って更(こう)生(せい)しろって　分(わ)かってないね！技(ぎ)術(じゅつ)を持(も)ったって元(もと)パンパンだってわかったら　どこも雇(やと)ってくんないよ

     Sore de panpan kara ashi o aratte kōsei shiro tte Wakatte-nai ne! Gijutsu o motta tte moto panpan datte wakattara Dokomo yatotte-kunnai yo

     They say that working girls are turning over a new leaf and rehabilitating themselves. Don't you get it! The skills that former sex workers have – they're useful anywhere.