Condensation inside windows? Some (3)
I believe the answer is:
dew
'condensation' is the definition.
(dew is a kind of condensation)
'inside windows? some' is the wordplay.
'some' says the answer is hidden in the clue.
'DEW' is hidden within 'inside windows'.
(Other definitions for dew that I've seen before include "'The foggy, foggy - - ' (song)" , "Morning condensation as on grass" , "Condensation at beginning or end of day" , "The damp of early morning" , "Overnight condensation" .)