The fog was avoided, I hear (4)
I believe the answer is:
mist
'the fog' is the definition.
(mist is a kind of fog)
'avoided i hear' is the wordplay.
'avoided' becomes 'missed' (missing is a kind of avoiding).
'i hear' shows a homophone (sound like).
'missed' sounds like 'MIST'.
'was' acts as a link.
(Other definitions for mist that I've seen before include "Cloud; thin fog" , "Haze" , "Obscure" , "Fret" , "Watery vapour" .)