The most common and most likely answer to this crossword clue is the 9 letter word UNWELCOME
I've seen this crossword clue in The Guardian
U
N
W
E
L
C
O
M
E
More clues leading to the result UNWELCOME
- New locum changed drug, accepted reluctantly
- ‘Loose women’: clue de trop
- Clue women misinterpreted as unpleasant
- Clue: ”Women possibly given a frosty reception‘
- New column we put in close to mine’s not liked
- Loose Women clue is distasteful
- Clue women possibly will find displeasing!
- Far from desirable Dicky gets end away – now, now!
- Poorly, cutting last visit as distasteful
Buddy explains!

The straight part
We know that "de trop" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case de trop = unwelcome.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 UNWELCOME mean?
UNWELCOME verb- To treat as unwelcome.
- Not welcome.