The most common and most likely answer to this crossword clue is the 5 letter word RILLE
R
I
L
L
E
More clues leading to the result RILLE
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 RILLE mean?
RILLE noun- A long, narrow depression that resembles a channel, found on the surface of various lunar and planetary bodies.