The most common and most likely answer to this crossword clue is the 7 letter word DEVIANT
I've seen this crossword clue in The Times
D
E
V
I
A
N
T
More clues leading to the result DEVIANT
- Abnormal sort of water in Derwent's banks
- Abnormal damage Roman road received
- Irregular drinker’s shakes diminished when imbibing spa water
- It’s simple to return in an environment of vacant detachment, though not normal
- Going astray through entering iniquitous place — Thailand’s capital
- Freaky and tailless, Satan sits on worker
Buddy explains!

The straight part
We know that "Abnormal" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case abnormal = deviant.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 DEVIANT mean?
DEVIANT noun- A person who deviates, especially from norms of social behavior.
- A thing, phenomenon, or trend that deviates from an expectation or pattern.
- Characterized by deviation from an expectation or a social standard.