The most common and most likely answer to this crossword clue is the 7 letter word WEIRDER
I've seen this crossword clue in Financial Times
W
E
I
R
D
E
R
Buddy explains!
The straight part
We know that "Stranger" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case stranger = weirder.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 WEIRDER mean?
WEIRDER adjective- Having an unusually strange character or behaviour.
- Deviating from the normal; bizarre.
- Of or pertaining to the Fates.
- Connected with fate or destiny; able to influence fate.
- Of or pertaining to witches or witchcraft; supernatural; unearthly; suggestive of witches, witchcraft, or unearthliness; wild; uncanny.
- Having supernatural or preternatural power.