The most common and most likely answer to this crossword clue is the 7 letter word FIDELIO
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More clues leading to the result FIDELIO
- Opera in which priest is bitten by dog?
- Contrarily put on Grease though opera's wanted
- Work of art showing priest in dog collar
- Priest feeds dog? That’s 15’s work!
- Dog biting priest in opera
- Sloshed, I initially fell over in opera
- Poem about lubed up regular in Covent Garden?
- Love, I managed, if in a roundabout way, to see an opera
Buddy explains!

The straight part
We know that "an opera" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case an opera = fidelio.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.