The most common and most likely answer to this crossword clue is the 5 letter word JAZZY
I've seen this crossword clue in Financial Times
J
A
Z
Z
Y
More clues leading to the result JAZZY
Buddy explains!

The straight part
We know that "Gaudy" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case gaudy = jazzy.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does JAZZY mean?
JAZZY adjective- In the style of jazz.
- Flashy or showy.
- Lacking focus; jittery or jangly.