The most common and most likely answer to this crossword clue is the 8 letter word FORCIBLE
I've seen this crossword clue in Financial Times
F
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More clues leading to the result FORCIBLE
Buddy explains!
The straight part
We know that "Strong" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case strong = forcible.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 FORCIBLE mean?
FORCIBLE adjective- Done by force, forced.
- (rare or obsolete) Having (physical) force, forceful.
- Having a powerful effect; forceful, telling, strong, convincing, effective.
- Able to be forced.