The most common and most likely answer to this crossword clue is the 5 letter word NEATH
I've seen this crossword clue in The Daily Telegraph
N
E
A
T
H
More clues leading to the result NEATH
- It was once under a town in Wales
- Excellent American hotel down under
- Smart hotel in Welsh town
- Below Old Bull and Bush at the end
- Elegantly simple opener from Hitchin Town
- Straight over brow of hill, Welsh town
- Fine athlete covers this bit of Wales
- Welsh town without water
- Welsh rugby club has a cow on the goalpost
- Well-ordered hospital somewhere in the Principality
Buddy explains!

The straight part
We know that "Welsh town" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case welsh town = neath.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 NEATH mean?
NEATH preposition- Beneath.