Film about love is soppy (5)
I believe the answer is:
'soppy' is the definition.
(both can mean wet or damp)
'film about love' is the wordplay.
'film' becomes 'mist' (to film over is to mist or fog over).
'about' indicates putting letters inside.
'love' becomes 'o' (love means zero in tennis).
'mist' enclosing 'o' is 'MOIST'.
'is' is the link.
(Other definitions for moist that I've seen before include "sloppy" , "Affected by tears, perhaps" , "bit wet" , "Damp or clammy" , "Slightly wet, damp" .)