The most common and most likely answer to this crossword clue is the 4 letter word REPP
R
E
P
P
Buddy explains!
The straight part
We know that "Cord" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cord = repp.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 REPP mean?
REPP noun- A fabric made of silk or wool, or of silk and wool, and having a transversely corded or ribbed surface.