A little of the mighty (4)

I believe the answer is:

emir

I'm a little stuck... Click here to teach me more about this clue!

'a little' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for emir that I've seen before include "Arabian ruler" , "Eastern chieftain" , "Arab prince" , "Ruler or chieftain in Arabia" , "Muslim ruler stuck in mire" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app