The most common and most likely answer to this crossword clue is the 8 letter word LIBRETTO
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More clues leading to the result LIBRETTO
- Looking up pet rodent, avoiding first dry old textbook
- Fancy Gilbert, heading off to his work
- See about translation of bitter words in opera
- Current bass about to join tenor among varied lot as part of an opera?
- . The script bore endless title, oddly enough
- Book for music: TS Eliot losing special composition about brother
- British Rail originally invested in new toilet book
- Party animal backing words to music
- Book old politician with backing of Right-ousting arsehole
- Love bitterly, mostly lost for words
Buddy explains!

The straight part
We know that "words in opera" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case words in opera = libretto.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 LIBRETTO mean?
LIBRETTO noun- The text of a dramatic musical work, such as an opera.
- A book containing such a text.