The most common and most likely answer to this crossword clue is the 4 letter word OLDE
I've seen this crossword clue in The Guardian
O
L
D
E
More clues leading to the result OLDE
Buddy explains!
The straight part
We know that "Quaintly charming" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case quaintly charming = olde.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 OLDE mean?
OLDE adjective- Of an object, concept, relationship, etc., having existed for a relatively long period of time.
- Having been used and thus no longer new or unused.
- Having existed or lived for the specified time.
- (heading) Of an earlier time.
- Tiresome after prolonged repetition.
- Said of subdued colors, particularly reds, pinks and oranges, as if they had faded over time.
- A grammatical intensifier, often used in describing something positive. (Mostly in idioms like good old, big old and little old, any old and some old.)
- Excessive, abundant.