A charge by Japanese soldiers with a bayonet or knife to kill the enemy in battle but also to die in honor if not effective, and to avoid being captured or surrendering. Used a lot WW2. Banzai means Long live the King/Emperor.
I was playing campaign on Call of Duty World at War and I was killed when a soldier used a Banzai Charge. BANZAI!!!!!!!!!!!!!!!!!!!!!!
by Favnila February 2, 2009
When you're having sex with a fat woman, usually 300lbs at the most, you allow the woman stand over you, and with you back first on the bed or floor looking up, the woman then yells "BANZAAAAAI!!" before doing a short jump and then slamming all of her doughiness down onto your chest or erect penis. Be careful though, performing this could EASILY result in a penile fracture if not done correctly

Named after the finishing move used by WWE Hall-of-Famer Yokozuna
Jesus Christ, that Banzai Drop almost broke my dick in half!
by Metallicajunkie October 5, 2018
Title character from the 1984 cult classic The Adventures of Buckaroo Banzai Across the 8th Dimension. Buckaroo, played by Peter Weller, is a world renowned neurosurgeon, particle physicist, race car driver, comic book hero and rock star.
"Wherever you go, there you are" -Buckaroo Banzai

"The only wasian 'superhero' in the history of American cinema is Buckaroo Banzai" - The Truth
by KidNapster June 6, 2005
Banzai is a Japanese song and the singer is a boy, so he is called the Banzai boi.
Use Banzai Boi when talking to people who like Banzai.
by U r Fat Mama Fat May 10, 2019
The act of overwhelming numbers Japanese pilots determined to give their lives in a brutal all out attack by crashing their planes into the cowardly enemy.
The large kamikaze banzai of Okinawa in '45 failed miserably as many pilots for the rising sun fell victim to Allied AA. The attack was ordered by General Mitsuru Ushijima.
by Qi Chow August 23, 2010
One who thinks their bowtie makes them look as suave as Buckaroo Banzai. Instead, they just look like a massive cuck.
Man, that Tucker Carlson is a real Cuckaroo Banzai...
by Strangelove8762 October 7, 2018
When a guy stands at one side of the room and his partner stands on the other side while bending over. The man then charges at his partner with his erection and tries to get it into his partner's vagina/ass at full running speed. If he misses, he could fracture his dick against his partner's ass.
Dude 1: Did you have sex with her last night?
Dude 2: Yeah. I tried banzai sex and I missed and broke my dick!
by JHAN1212 October 7, 2015