Result of Sun hacking into telecom company (5)
I believe the answer is:
ensue
'result' is the definition.
(synonyms)
'sun hacking into telecom company' is the wordplay.
'hacking' indicates an anagram.
'into' means one lot of letters goes inside another.
'telecom company' becomes 'ee' (British mobile network EE).
'sun' is an anagram of 'nsu'.
'nsu' put into 'ee' is 'ENSUE'.
'of' acts as a link.
(Other definitions for ensue that I've seen before include "Result in a particular way" , "Follow later" , "Come about, result in" , "Leading directly to" , "Come to pass" .)