The most common and most likely answer to this crossword clue is the 7 letter word ATTIRES
I've seen this crossword clue in Independent
A
T
T
I
R
E
S
More clues leading to the result ATTIRES
Buddy explains!
The straight part
We know that "Dresses/king in neckwear that goes with casual shirt" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dresses/king in neckwear that goes with casual shirt = attires.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 ATTIRES mean?
ATTIRES noun- (clothing) One's dress; what one wears; one's clothes.
- The single horn of a deer or stag.
- To clothe or adorn.