The most common and most likely answer to this crossword clue is the 5 letter word AMEER
I've seen this crossword clue in The Guardian
A
M
E
E
R
More clues leading to the result AMEER
- Dictator’s a pure and simple ruler in the Gulf
- Arab, 23, giving Ms Heard a change of heart
- Prince of foreign 9 using euro, originally in place of pound
- Prince appearing in dream, eerily
- A simple-sounding ruler?
- Muslim prince is consistently warm to English queen
- A paltry so-called Islamic prince
- Perhaps, a monarch earning extensive royalty, for starters
- . Ruler's a cat of sorts
Buddy explains!

The straight part
We know that "Prince" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case prince = ameer.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.