Comprehensive blog involved gangster (6)
I believe the answer is:
global
'comprehensive' is the definition.
('global' can be similar in meaning to 'comprehensive')
'blog involved gangster' is the wordplay.
'involved' indicates anagramming the letters (involved can mean confusing or complex).
'gangster' becomes 'al' (Al Capone).
'blog' is an anagram of 'glob'.
'glob'+'al'='GLOBAL'
(Other definitions for global that I've seen before include "Of the whole world, worldwide" , "Comprehensive" , "Relating to the whole world" , "international" , "Universal" .)