Talk about field event before start of school (7)
I believe the answer is:
discuss
'talk about' is the definition.
(to discuss something is to talk about it)
'field event before start of school' is the wordplay.
'field event' becomes 'discus' (discus is a kind of field event).
'before' says to put letters next to each other.
'start of' says to take the initial letters.
The first letter of 'school' is 's'.
'discus'+'s'='DISCUSS'
(Other definitions for discuss that I've seen before include "Consider" , "Verbally T [TREAT]" , "Settle" , "Go into" , "Argue" .)