Sadistic alien? (7)
I believe the answer is:
inhuman
This clue could be a double definition.
'sadistic' is the first definition.
(thesaurus)
'alien?' is the second definition.
Both the definition and answer are adjectives. Maybe you can see an association between them that I don't see?
Can you help me to learn more?
(Other definitions for inhuman that I've seen before include "Unfeelingly cruel" , "Pitiless - barbarous" , "Savage, brutal" , "Beastly" , "Without compunction" .)