The most common and most likely answer to this crossword clue is the 5 letter word GARDA
I've seen this crossword clue in Independent
G
A
R
D
A
More clues leading to the result GARDA
- Cop rejecting a tedious occupation
- A boring thing, looking back, for Irish police
- Copper overseas turned up a haul
- Police officer with a boring job going about
- Lake where a bore recedes
- Police officer held in regard, always
- Policeman abroad backed a tiresome activity
- Irish police turned troublesome
- Irish force a draw after a comeback
- The Irish Bill?
Buddy explains!

The straight part
We know that "Kerry’s busy" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case kerry’s busy = garda.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 GARDA mean?
GARDA noun- A member of the national police force of the Republic of Ireland, the Gardaí.