Flipping poor housing close to river's dingy (4)
I believe the answer is:
drab
'dingy' is the definition.
(both can mean gloomy or dark)
'flipping poor housing close to river's' is the wordplay.
'flipping' says the letters should be written backwards.
'poor' becomes 'bad' (similar in meaning).
'housing' means one lot of letters goes inside another.
'close to' suggests the final letters (the close of something is the end).
The final letter of 'river' is 'r'.
'bad' going around 'r' is 'bard'.
'bard' back-to-front is 'DRAB'.
(Other definitions for drab that I've seen before include "Dull kind of bard" , "Dull, uninteresting" , "Drearily dull; slattern" , "Dull and colourless" , "Dingy, dull" .)