Definition from Wiktionary, the free dictionary
- with a wham, with a wallop
- genkotsu de boin to naguru
- to hit someone wham with [your] fists
- with a boing, with a sproing
- boin to haneru
- to leap with a sproing
Takes the particle と (to).
- large breasts
2009 April 24, Junji Majima as Daisuke Aoki, “たのしいうんどうかい (Tanoshii Undōkai) "Fun Athletic Meet"”, Kodomono Jikan Nigakki 2nd OVA episode, Tokyo: Studio Barcelona, as published 2009, at 5 minutes, 20seconds:
- "There's a teachers' relay, too, but...I wonder if you can run with breasts that big... 'Boin' sensei."
- ano ko wa sugoi boin da yo.
- That girl is stacked. / That girl has great boobs.
- 巨乳 (kyonyū)