The most common and most likely answer to this crossword clue is the 4 letter word KITH
I've seen this crossword clue in The Guardian
K
I
T
H
More clues leading to the result KITH
- Moon, perhaps, shunning European friends
- Old friends bringing equipment to hospital
- Tackle Henry’s mates
- Old friends like Christopher and Elspeth at the end
- Old friends think it harms cases
- Tackle hard friends and acquaintances
- Christopher, husband in social group
- Friends hot on equipment?
- Lisp a salutation to friends
- Old acquaintance
Buddy explains!

The straight part
We know that "Old friends" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case old friends = kith.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 KITH mean?
KITH noun- Friends and acquaintances.
- (rural) An acquaintance or a friend.