Charlady thinner after cold (7)
I believe the answer is:
cleaner
'charlady' is the definition.
(I've seen this before)
'thinner after cold' is the wordplay.
'thinner' becomes 'leaner' ('lean' can be a synonym of 'thin').
'after' says to put letters next to each other.
'cold' becomes 'c' (eg on taps).
'leaner' after 'c' is 'CLEANER'.
(Other definitions for cleaner that I've seen before include "Less soiled" , "Maybe Daily" , "Eg, char" , "More hygienic" , "Chemical agent for removing dirt" .)