In bad visibility, note the footballer's error (3)
I believe the answer is:
fog
'in bad visibility' is the definition.
'fog' can be an answer for 'visibility' (thesaurus). I am not certain of the 'in bad' bit.
'note the footballer's error' is the wordplay.
'note' becomes 'f' (musical note).
'the footballer's error' becomes 'og' (I can't justify this - if you can you should give a lot more credence to this answer).
'f'+'og'='FOG'
Can you help me to learn more?
(Other definitions for fog that I've seen before include "Impenetrable mist" , "Confusion" , "second growth of grass" , "Heavy mist" , "Miasma" .)