Land accommodating quiet reptile (8)
I believe the answer is:
terrapin
'reptile' is the definition.
(I know that terrapin is a type of turtle)
'land accommodating quiet' is the wordplay.
'land' becomes 'terrain' (terrain is land or territory).
'accommodating' is an insertion indicator.
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'terrain' placed around 'p' is 'TERRAPIN'.
(Other definitions for terrapin that I've seen before include "Partner I found for freshwater tortoise" , "Web-footed turtle" , "Give out" , "Little turtle" , "temporary building" .)