Computer confused the English hacker (7)
I believe the answer is:
machete
'hacker' is the definition.
(blade used to hack at things)
'computer confused the english' is the wordplay.
'computer' becomes 'Mac' (Apple Mac computer).
'confused' indicates anagramming the letters.
'english' becomes 'E' (abbreviation).
'the' is an anagram of 'het'.
'mac'+'het'+'e'='MACHETE'
(Other definitions for machete that I've seen before include "Knife for hacking" , "Teach me with large jungle knife" , "Broad heavy knife common in Central America" , "Jungle chopper" , "Broad heavy knife used in S American jungles" .)