The most common and most likely answer to this crossword clue is the 10 letter word BRIGHTENED
I've seen this crossword clue in The Times
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More clues leading to the result BRIGHTENED
Buddy explains!
The straight part
We know that "cheered up" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cheered up = brightened.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 BRIGHTENED mean?
BRIGHTENED 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.