Level contests essentially embodying sport (4)
I believe the answer is:
true
'level' is the definition.
(I've seen this in another clue)
'contests essentially embodying sport' is the wordplay.
'essentially' says to take the centre.
'embodying' is an insertion indicator (to embody can mean to contain or include).
'sport' becomes 'RU' (rugby union).
The middle of 'contests' is 'te'.
'te' going around 'ru' is 'TRUE'.
(Other definitions for true that I've seen before include "Consistent with fact" , "comfortable" , "Dependable -- loyal" , "Exact; faithful" , "Real; loyal" .)