The most common and most likely answer to this crossword clue is the 9 letter word CODPIECES
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Buddy explains!
The straight part
We know that "They ‘enhanced’ Crown Jewels/which chippy’s cabinet displays" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they ‘enhanced’ crown jewels/which chippy’s cabinet displays = codpieces.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 CODPIECES mean?
CODPIECES noun- A part of male dress in the 15th and 16th centuries, worn in front of the breeches to cover the male genitals.
- A conspicuous protection for the male genitals in a suit of plate armor.