The most common and most likely answer to this crossword clue is the 6 letter word MALLEE
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Buddy explains!
The straight part
We know that "arid region" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case arid region = mallee.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 MALLEE mean?
MALLEE noun- A type of scrubland with low-growing thick eucalypts, characteristic of certain parts of Australia.
- Any semi-desert region of Australia where such scrub is the predominant vegetation.
- Any of several low-growing eucalypts characteristic of such scrubland, especially Eucalyptus dumosa, Eucalyptus oleosa, and Eucalyptus socialis.
- The growth habit of certain eucalypt species that grow with multiple stems springing from an underground lignotuber, shared by species of related genera.
- A member of a caste in South Asia whose traditional occupation is gardening; hence, any native gardener.
- Money, cash.