Off-base and Unapt

Off-base adjective - Located outside a military base.

Unapt and off-base are semantically related in improper topic. In some cases you can use "Unapt" instead an adjective phrase "Off-base", when it comes to topics like not suitable.

Unapt adjective - Not appropriate for a particular occasion or situation.

Off-base and unapt are semantically related in improper topic. Sometimes you can use "Off-base" instead an adjective "Unapt".