The most common and most likely answer to this crossword clue is the 8 letter word BANDANAS
I've seen this crossword clue in The Sunday Telegraph
B
A
N
D
A
N
A
S
More clues leading to the result BANDANAS
Buddy explains!
The straight part
We know that "silk neckwear" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case silk neckwear = bandanas.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 BANDANAS mean?
BANDANAS noun- A large kerchief, usually colourful and used either as headgear or as a handkerchief, neckerchief, bikini, or sweatband.
- A style of calico printing, in which white or bright spots are produced upon cloth previously dyed a uniform red or dark colour, by discharging portions of the color by chemical means, while the rest of the cloth is under pressure.