The most common and most likely answer to this crossword clue is the 6 letter word REJOIN
R
E
J
O
I
N
Buddy explains!
The straight part
We know that "come back" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case come back = rejoin.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 REJOIN mean?
REJOIN verb- To join again; to unite after separation.
- To come, or go, again into the presence of; to join the company of again.
- To state in reply; -- followed by an object clause.
- : To answer to a reply.
- To answer, as the defendant to the plaintiff's replication.
- In US patent law To re-insert a patent claim, typically after allowance of a patent application, applied to patent claims that had been withdrawn from examination under a restriction requirement, based on rejoinder .