Reptile papa buried in ground (8)
I believe the answer is:
terrapin
'reptile' is the definition.
(terrapin is a kind of reptile)
'papa buried in ground' is the wordplay.
'papa' becomes 'P' (NATO / phonetic alphabet).
'buried in' is an insertion indicator (inserted letters get buried).
'ground' becomes 'terrain' (terrain is land or ground).
'p' put into 'terrain' is 'TERRAPIN'.
(Other definitions for terrapin that I've seen before include "edible, freshwater reptile" , "Aquatic tortoise" , "Give out" , "Water tortoise" , "Small species of turtle" .)