The most common and most likely answer to this crossword clue is the 5 letter word NORIA
N
O
R
I
A
Buddy explains!
The straight part
We know that "irrigation device" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case irrigation device = noria.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 NORIA mean?
NORIA noun- A water wheel with attached buckets, used to raise and deposit water.
- Any machine using buckets to raise water to an aqueduct.