Ill-timed and Off-base

Ill-timed adjective - Badly timed.

Off-base and ill-timed are semantically related In some cases you can use "Off-base" instead an adjective phrase "Ill-timed".

Off-base adjective - Located outside a military base.

Ill-timed and off-base are semantically related in improper topic. Sometimes you can use "Ill-timed" instead an adjective phrase "Off-base", if it concerns topics such as not suitable.