The Greek that is translated as “fool” (in Matthew 5:22) or “insane” is translated in Mairasi as “(your/their) vision has dried up.” The opposite (“sane”) is “vision is well-split” (see right mind / sound-minded).

In Elhomwe it is idiomatically translated as “not grasping the head.” (Source: project-specific translation notes in Paratext)

See also You are out of your mind!.