The most common and most likely answer to this crossword clue is the 6 letter word SHINED
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Buddy explains!

The straight part
We know that "Made brilliant" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case made brilliant = shined.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 SHINED mean?
SHINED verb- To emit light.
- To reflect light.
- To distinguish oneself; to excel.
- To be effulgent in splendour or beauty.
- To be eminent, conspicuous, or distinguished; to exhibit brilliant intellectual powers.
- To be immediately apparent.
- To create light with (a flashlight, lamp, torch, or similar).
- To cause to shine, as a light.
- To make bright; to cause to shine by reflected light.
- To cause (something) to shine; put a shine on (something); polish (something).
- To polish a cricket ball using saliva and one’s clothing.