Meadow — wide opening remains, however (9)
I believe the answer is:
leastways
'however' is the definition.
'meadow wide opening remains' is the wordplay.
'meadow' becomes 'lea' (a lea is a grassy area).
'wide' becomes 'w' (abbreviation e.g. in cricket).
'opening' means one lot of letters goes inside another (some letters open a gap in others).
'remains' becomes 'stays' (to stay in a place is to remain there).
'w' going within 'stays' is 'stways'.
'lea'+'stways'='LEASTWAYS'
(Other definitions for leastways that I've seen before include "at any rate" , "in any event" , "anyhow" , "If nothing else" , "As a minimum" .)