Gloomy maids wandering by lake (6)
I believe the answer is:
dismal
'gloomy' is the definition.
('dismal' can be a synonym of 'gloomy')
'maids wandering by lake' is the wordplay.
'wandering' is an anagram indicator.
'by' says to put letters next to each other.
'lake' becomes 'l'.
'maids' with letters rearranged gives 'disma'.
'disma'+'l'='DISMAL'
(Other definitions for dismal that I've seen before include "Dull; doleful" , "Gloomy and depressing like winter weather" , "Sad, gloomy" , "Gloomy, bleak" , "Very disappointing" .)