De or het broeder-overste?

The correct Dutch article is:

de broeder-overste

Rule Words ending in -te: usually de. See the rule

How to use broeder-overste

the broeder-overstede broeder-overste
this broeder-overstedeze broeder-overste
that broeder-overstedie broeder-overste
our broeder-oversteonze broeder-overste
your broeder-overstejouw broeder-overste
every broeder-oversteelke broeder-overste
which broeder-overste?welke broeder-overste?
a big broeder-overste / the big broeder-oversteeen grote broeder-overste, de grote broeder-overste