From Oxford, the traditional dictionary:

gen·o·cide

noun

the deliberate killing of a large number of people from a particular nation or ethnic group with the aim of destroying that nation or group.

What part of that is Israel not doing?

Or we can go with the legal definition from the 1948 Convention on the Prevention and Punishment of the Crime of Genocide linked from https://www.un.org/en/genocideprevention/genocide.shtml.

Article II

In the present Convention, genocide means any of the following acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group, as such:

• (a) Killing members of the group;
• (b) Causing serious bodily or mental harm to members of the group;
• (c) Deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part;
• (d) Imposing measures intended to prevent births within the group;
• (e) Forcibly transferring children of the group to another group.

The only one in question is the last point, but any single one of those points means it's a genocide.