Mistake from Falcao, oddly heading wide (4)
I believe the answer is:
flaw
'mistake' is the definition.
(thesaurus)
'falcao oddly heading wide' is the wordplay.
'oddly' indicates alternate letters (letters in the odd-numbered positions are used).
'heading' means one lot of letters go next to another (some letters go in front of or head others).
'wide' becomes 'w' (abbreviation e.g. in cricket).
The alternating letters of 'falcao' are 'fla'.
'fla'+'w'='FLAW'
'from' is the link.
(Other definitions for flaw that I've seen before include "(Make) defect(ive)" , "Error in theory or plan" , "failing" , "weak spot" , "sudden rush" .)