Belittle reading about alien returning (9)
I believe the answer is:
denigrate
'belittle' is the definition.
(I know that belittle is a more specific form of the action belittle)
'reading about alien returning' is the wordplay.
'about' is an anagram indicator.
'alien' becomes 'et' (extra terrestrial).
'returning' is a reversal indicator.
'et' in reverse letter order is 'te'.
'reading' with letters rearranged gives 'denigra'.
'denigra'+'te'='DENIGRATE'
(Other definitions for denigrate that I've seen before include "Defame" , "Criticise, belittle" , "Unfairly criticise" , "Blacken" , "put down" .)