The most common and most likely answer to this crossword clue is the 7 letter word KINGLET
I've seen this crossword clue in The Daily Telegraph
K
I
N
G
L
E
T
Buddy explains!

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 KINGLET mean?
KINGLET noun- A petty king; a king ruling over a small or unimportant territory.
- Any of several birds of the family Regulidae.