Bury in plain terms (5)
I believe the answer is:
inter
'bury' is the definition.
(to inter is to put into the ground)
'in plain terms' is the wordplay.
'in' says the answer is hidden in the clue.
'INTER' is hidden within 'plain terms'.
(Other definitions for inter that I've seen before include "Milan FC" , "Place in ground" , "Bury a body - in the middle?" , "Send to ground" , "somewhere between ..." .)