It takes a very long time for The Wise Guys to lose the head (4)
I believe the answer is:
ages
'for the wise guys to lose the head' is the definition.
I can't tell whether this defines the answer.
'it takes a very long' is the wordplay.
'it' becomes 'e' ('e' can mean 'electronic' which is similar to 'IT').
'takes' is an insertion indicator (take can mean to capture or invade).
'very long' becomes 'gs' (I am not sure about this - if you are sure you should believe this answer much more).
'a'+'gs'='ags'
'e' put within 'ags' is 'AGES'.
'time' acts as a link.
Can you help me to learn more?
(Other definitions for ages that I've seen before include "Grows old like sage" , "(What seems) a very long time" , "Indefinitely long time" , "Historical eras" , "A long time (colloq.)" .)