Field events terribly obvious (4-7)
I believe the answer is:
self-evident
'obvious' is the definition.
(I've seen this before)
'field events terribly' is the wordplay.
'terribly' indicates anagramming the letters.
'field'+'events'='fieldevents'
'fieldevents' anagrammed gives 'SELF-EVIDENT'.
(Other definitions for self-evident that I've seen before include "Not needing to be demonstrated" , "Not needing to be explained" , "Not requiring further explanation" , "Needing no explanation" , "Obvious" .)