Smart but gaudy? (6)

I believe the answer is:

bright

I'm a little stuck... Click here to teach me more about this clue!

This clue might be a double definition.

'smart' is the first definition.
(I know that smart can be written as bright)

'gaudy?' is the second definition.
Both the definition and answer are adjectives. Maybe there's a link between them I don't understand?

'but' is the link.

Can you help me to learn more?

(Other definitions for bright that I've seen before include "Jolly" , "Vivid; cheerfully lively" , "Mentally quick or radiating light" , "Illuminated" , "Clever - dazzling" .)

I've seen this clue in the Evening Standard.

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