Definition of “hack” - Learner’s Dictionary

hack

verb [ I, T ] uk us /hæk/
CUT

to cut something roughly into pieces:

The victim had been hacked to death.
COMPUTER

to use a computer to illegally get into someone else's computer system and read the information that is kept there:

Two British youths were caught hacking into government computers.
TELEPHONE [ often passive ]

to illegally and secretly listen to someone else's telephone conversations or to the messages left on someone else's telephone:

The actor believes that his phone was hacked by the newspaper.

(Definition of “hack verb” from the Cambridge Learner's Dictionary © Cambridge University Press)