IPA: /ˈkɒstjʊmi/
KK: /ˈkɑːstʊmi/
Describing something that is overly elaborate or decorative, resembling a costume.
The play had a very costumey feel, with bright colors and extravagant outfits.
The word 'costumey' is derived from 'costume' (from French *costume*, meaning a style of dress) and the suffix '-y' (meaning characterized by). Therefore, 'costumey' refers to something characterized by or resembling a costume.
Think of 'costume' as a style of dress, and remember that 'costumey' means something that has the characteristics of a costume.