of sound mind, mentally healthy
While "insane" might seem more obvious to people as an ableist word to use, the subtle connotation that sanity is good implicitly suggests that insanity, its opposite, is bad.
Connoting sanity (which is an assessment of a person's neurological status—a medical condition that largely can't be changed) with being well-thought out, reasonable, sensible (or mindful of an event or series of events) reinforces the ableist idea that sanity (being neurotypical or mentally well and abled) is good, and its opposite of insanity (being neurodivergent or mentally ill and disabled), is bad.
Using "sane" reinforces the system that excludes mentally ill and disabled people, reinforcing negative biases against them. Using this language causes harm to mentally ill, neurodivergent, and disabled people.
By using this ableist language, we are perpetuating violence against people who experience mental or psychological disabilities. Using this language perpetuates those systems and language of harm, regardless of our intent.
Be more specific. Typically we can find an alternate definition by taking time to reflect on what criteria we hope our test can meet and what kind of feedback we're hoping to gain.