You Do Need power plug adapter while traveling from Israel to Namibia.

Here is Why You Need An Adapter

The outlet and plug type used in Namibia are D and M and in Israel are C and H. This is how they look like.

Israel

In Israel, outlets of type C and H are in use.

Type C

Type H

Namibia

In Namibia, outlets of type D and M are in use.

Type D

Type M