Hoard clipped Indian coin, that's plain! (7)
I believe the answer is:
savanna
'plain' is the definition.
(I've seen this before)
'hoard clipped indian coin' is the wordplay.
'hoard' becomes 'save' (I've seen this before).
'clipped' means to remove the last letter.
'indian coin' becomes 'anna' (I have seen 'Old coin' mean 'anna' so perhaps 'coin' could also mean 'anna'. I am not sure about the 'indian' bit.).
'save' with its last letter removed is 'sav'.
'sav'+'anna'='SAVANNA'
'that's' acts as a link.
Can you help me to learn more?
(Other definitions for savanna that I've seen before include "Flat, tropical grassland" , "Tropical African grasslands" , "Grassy (African) plain" , "Open grasslands of Africa" , "African grassland" .)