noun / verb
hack
HAK/hæk/
Access to a computer system by bypassing its security.
The company investigates a hack that exposes customers' private records.

Etymology
Hack apparently formed from hacker, whose computer use is said to have first described enthusiastic software experimenters before naming unauthorized intruders. Its deeper connection with chopping or routine hired work remains uncertain.
In context
security is is a big problem someone trying to hack your system if they're hacking into your system it's probably causing network or system behavior that is abnormal in some way
More examples
- Someone hacked into my email account last night.
- Attackers try to hack the server by guessing weak passwords.
- The bank discovered two hacks during its security review.
Forms
hack · hacks · hacked · hacking
hacker noun — Someone who gains unauthorized computer access.