The most common and most likely answer to this crossword clue is the 6 letter word GARTER
I've seen this crossword clue in Independent
G
A
R
T
E
R
More clues leading to the result GARTER
- Band: T Rex up wearing outrageous gear
- Stocking aid supporting artery to some extent
- The aged are welcomed into German band
- Crowd round King and Queen to get knighthood
- Soak newspaper up in a flash?
- Strip for one who puts on clothes?
- One audibly snaps round end of suspender
- Band involved in hold-up storing paintings in Germany
- Grand talent by Queen’s supporting band?
- Eltonturns up full of skill in band
Buddy explains!

The straight part
We know that "knighthood" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case knighthood = garter.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 GARTER mean?
GARTER noun- A band worn around the leg to hold up a sock or stocking.
- A bendlet.
- To fasten with a garter