underdressed

US /ˌʌn.dɚˈdrest/
UK /ˌʌn.dɚˈdrest/
"underdressed" picture
1.

salah kostum, kurang formal

wearing clothes that are too informal for a particular occasion

:
I felt completely underdressed at the fancy restaurant.
Saya merasa benar-benar salah kostum di restoran mewah itu.
She was worried she would be underdressed for the gala.
Dia khawatir akan salah kostum untuk acara gala.