The most common and most likely answer to this crossword clue is the 7 letter word NOXIOUS
I've seen this crossword clue in The Daily Telegraph
N
O
X
I
O
U
S
More clues leading to the result NOXIOUS
- Just after rising up Sioux, maltreated, harmful
- Perhaps brave to swap sides after earlier refusal is harmful
- It’s deadly with no end to tax and debts
- We French embracing axiom: being unclothed is bad for you
- Deadly beast on island is captured by common sense
- Unwholesome sense about Times and Indy
- Foul where old team breaks common sense
Buddy explains!
The straight part
We know that "Foul" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case foul = noxious.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 NOXIOUS mean?
NOXIOUS adjective- Harmful; injurious.