glad rags 
plural noun informal
Clothes for a special occasion; smart or showy clothes: she changed out of her glad rags and tugged on old jeans...
- Reviewers are likely to mistake, if not nudity for new clothes, bizarre glad rags for haute couture.
- It's the night of nights for the science glitterati of Australia, a chance for scientists and their mates to whip off their lab coats and don their glad rags.
- Wear an old coat over your glad rags, though - sparks will fly.
Synonyms
best clothes, finery, Sunday best
informal best bib and tucker
- cabbage-tree hat mob
- cabbage-tree mob
- cabbage white
- cabbageworm
- cabbagey
- cabbaging
- Cabbala
- cabbalism
- life and limb
- life and times
- life and work
- life and works
- life assemblage
- life assurance
- lifebelt
- lifeblood
- lifeboat
- lifeboat day
- lifeboatman
- lifeboatsman
- lifeboat station
- life-breath
- lifebuoy
- life care
- lifecast