The most common and most likely answer to this crossword clue is the 4 letter word KARA
K
A
R
A
Buddy explains!
The straight part
We know that "It carries significance for Sikhs" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it carries significance for sikhs = kara.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 KARA mean?
KARA noun- A bangle worn by Sikhs, one of the five Ks, to remind them to do God's work.