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

Here is Why You Need An Adapter

The outlet and plug type used in Namibia are D and M and in Cambodia are A, C and G. This is how they look like.

Cambodia

In Cambodia, outlets of type A, C and G are in use.

Type A

Type C

Type G

Namibia

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

Type D

Type M