The most common and most likely answer to this crossword clue is the 7 letter word SARACEN
I've seen this crossword clue in The Daily Telegraph
S
A
R
A
C
E
N
More clues leading to the result SARACEN
- Old Arab people hospitalised?
- Fighter of old in hospital housing ethnic group
- Cross opponent of the Middle Ages
- Hospital screening career rugby player?
- Active ethnic group in Senegal is Arab
- Medieval warrior from small tribe featured in article
- Old Arab nation included in small article
- A contest between two Poles and old Arab
- Poles holding a sporting event for Arab
- Arab in rush to be admitted to hospital
Buddy explains!

The straight part
We know that "old Arab" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case old arab = saracen.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.