Cruel to bury outside a prison base (8)
I believe the answer is:
inhumane
'cruel' is the definition.
(similar in meaning)
'bury outside a prison base' is the wordplay.
'bury' becomes 'inhume' (I've seen this in another clue).
'outside' means one lot of letters goes inside another (some letters go outside others).
'base' suggests the final letters (the base of the word).
The last letter of 'prison' is 'n'.
'a'+'n'='an'
'inhume' placed around 'an' is 'INHUMANE'.
'to' acts as a link.
(Other definitions for inhumane that I've seen before include "Callous" , "Cruel" , "Heartless" , "Not compassionate" .)