Global virus heartless alien spread (9)
I believe the answer is:
universal
'global' is the definition.
(thesaurus)
'virus heartless alien spread' is the wordplay.
'heartless' means to remove the middle letters.
'spread' is an anagram indicator.
'alien' with its centre removed is 'alen'.
'virus'+'alen'='virusalen'
'virusalen' is an anagram of 'UNIVERSAL'.
(Other definitions for universal that I've seen before include "Sort of joint" , "Belonging to the whole world" , "Widespread, worldwide" , "Ubiquitous" , "Everywhere applicable" .)