The most common and most likely answer to this crossword clue is the 8 letter word SLEEVEEN
S
L
E
E
V
E
E
N
Buddy explains!
The straight part
We know that "Irish one" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case irish one = sleeveen.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 SLEEVEEN mean?
SLEEVEEN noun- A dishonest person; a trickster, usually from a rural area.