Tidy Welsh town? Almost (4)
I believe the answer is:
neat
'tidy' is the definition.
('neat' can be similar in meaning to 'tidy')
'welsh town? almost' is the wordplay.
'welsh town?' becomes 'neath' (I've seen this before).
'almost' means to remove the last letter (most of the word but not all of it).
'neath' with its final letter taken off is 'NEAT'.
(Other definitions for neat that I've seen before include "(Of alcohol) not diluted" , "In good order, tidy" , "without water being added" , "Excellent American" , "Orderly, uncluttered" .)