How to define cybercrime?

Accord­ing to ANSSI, cyber­crime regroups offend­ers’ acts or acts tar­get­ing inter­na­tion­al treaties or nation­al laws, using net­works or infor­ma­tion sys­tems as means to car­ry out an offence or a crime.

Source: ANSSI

See the page on cyber­at­tack.