Wakefield players in college (7)
I believe the answer is:
'college' is the definition.
(I've seen this before)
'wakefield players in' is the wordplay.
I cannot really see how this works, but
'in' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for trinity that I've seen before include "Threesome" , "Cambridge college founded by Henry VIII" , "House" , "Group of three considered as one" , "Father, Son and Holy Spirit" .)