The most common and most likely answer to this crossword clue is the 6 letter word GLARES
I've seen this crossword clue in The Times
G
L
A
R
E
S
More clues leading to the result GLARES
Buddy explains!

The straight part
We know that "Evil looks" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case evil looks = glares.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 GLARES mean?
GLARES noun- An intense, blinding light.
- Showy brilliance; gaudiness.
- An angry or fierce stare.
- A call collision; the situation where an incoming call occurs at the same time as an outgoing call.
- A smooth, bright, glassy surface.
- A viscous, transparent substance; glair.