ウェディングスーツ

noun

lounge suit (esp. for weddings)

A formal daytime suit worn by male guests or the groom at weddings; not a tuxedo. In Japanese usage, often implies a specific dress code for wedding ceremonies.

from English wedding suit

• 結けっ婚こん式しきにはウェディングスーツを着きていくつもりだ。

  I plan to wear a wedding suit to the ceremony.