The most common and most likely answer to this crossword clue is the 7 letter word AGONISE
I've seen this crossword clue in The Times
A
G
O
N
I
S
E
More clues leading to the result AGONISE
- Surprisingly, age is no worry
- Iago’s end almost excited worry
- Mature bears on island struggle
- Ace is away boxing, causing worry
- Worry intensely since returning in London area
- Time to welcome revolutionary Chinese brood
- Struggle in past to overturn English mistake
- An attempt is ultimately futile to defend New Labour
- Worry easing somehow surrounding Leader of Opposition
- Worry is in past over Tyneside
Buddy explains!

The straight part
We know that "worry" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case worry = agonise.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 AGONISE mean?
AGONISE verb- To writhe with agony; to suffer violent anguish.
- To struggle; to wrestle; to strive desperately, whether mentally or physically.