The most common and most likely answer to this crossword clue is the 8 letter word BRIGHTEN
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More clues leading to the result BRIGHTEN
- Become sunnier in resort, we hear
- To cheer up British nurse, it’s correct to get inside!
- Just has been half-heartedly about to cheer
- Cheer up English football club broadcast
- Get lighter energy for nothing in English resort
- Nicholson embraces the right to cheer up
- Approved accessing Scottish peak in lift
- Clear up venue sometimes chosen for parties, as we hear
- Turn gay in seaside town, say
- Clear up and give correct points to club, finally
Buddy explains!

The straight part
We know that "Become sunnier" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case become sunnier = brighten.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 BRIGHTEN mean?
BRIGHTEN verb- To make bright or brighter in color.
- To make illustrious, or more distinguished; to add luster or splendor to
- To make more cheerful and pleasant; to enliven
- To grow bright, or more bright in color; to clear up
- To become brighter or more cheerful in mood
- To make acute or witty; to enliven.