The most common and most likely answer to this crossword clue is the 11 letter word FIRST-CLASS
I've seen this crossword clue in Financial Times
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More clues leading to the result FIRST-CLASS
Buddy explains!
The straight part
We know that "Excellent" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case excellent = first-class.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 FIRST-CLASS mean?
FIRST-CLASS noun- (A status, section, etc which is of) premier rank.
- The third year of primary school, following after the junior and senior infant levels.
- One of two classes of city government in the U.S. state of Kentucky, in which cities elect a mayor and aldermen.