Way of thinking is concerned about alien (4-3)
I believe the answer is:
mind-set
'way of thinking' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'concerned about alien' is the wordplay.
'concerned about' becomes 'minds' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'alien' becomes 'et' (extra terrestrial).
'minds'+'et'='MIND-SET'
'is' is the link.
Can you help me to learn more?
(Other definitions for mind-set that I've seen before include "Characteristic mental attitude" , "Send Tim (anag.)" , "Fixed way of thinking" , "Habitual way of thinking" .)