WA DA DA [2021]
wagwan 
wanna  
wally-world 
wannabe 
way 
wbu 
WBY
WCW
wedgie
weird / weirdo 
welc / welcs / welcy 
Well played. 
WFH [2021]
What a nuisance! [2021]
What even!
whatever 
Whatever you say. [2021]
whatevs /whatevz 【ベスト100スラング72位】  
What a coincidence!  [2022]
What a nuisance [2021]
what the heck 
What will be, will be.
what's-his-face 
what's the occasion?
What's up? 
While we are at it
whip 
wildin/ wildin' out
Who dares wins.
whoa 
whoadi / whodi 
With that being said
woop woop 
woot woot 
word 
word is bond. 
wtf 【ベスト100スラング92位】