The most common and most likely answer to this crossword clue is the 4 letter word AULD
I've seen this crossword clue in The Daily Telegraph
A
U
L
D
More clues leading to the result AULD
- Ancient Scottish notice protecting the centre of Mull
- Those at the front in detachment lining up and climbing over the hill in Scotland?
- Ancient Scottish lord weighed down by gold
- Ancient Glaswegian notice covering the centre of Mull
- Ageing Glaswegian oddly rejected casual dress at first
- Old Scottish apothecaries use lower dosages initially
Buddy explains!

The straight part
We know that "Ancient" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ancient = auld.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 AULD mean?
AULD adjective- Old