I understand how it's applied as a medical term in the English language, but for me I don't describe the way I feel as malaise in those terms either. Would you describe yourself feeling malaise to healthy people though? I don't think they would consider you disabled.
I try not to use too many medical /technical / high-level vocabulary terms in my everyday conversatins... but... this is me. Bona fide nerd. Bookish, and social skills not great.
However I think the point of defining terms in definition criteria is usually to reach doctors.
Edit: however I agree malaise, even the best medical meaning (and sorry if I put too many posts about this), is not enough by itself, to describe what we have. /edit
To healthy or mildly unhealthy people I have sometimes (when I was better than now) asked them to try and think of the worst flu they ever had.... add a bad migraine... insomnia for many weeks.... imagine they have just run a marathon (only no high from the exercise or from finish line, just the exhaustion and pain).... all at once. Yeah that's a little like what I feel. Every day. They were typically appropriately impressed.
Other times I say I have something that is a little like MS, only less well known. Or a cross between MS and Lupus. Or just leave it at 'disabled'.
Or I do the whole ME, neuro-immune, cheezy name CFS, not well diagnosed speech. Maybe adding that many diseases, recent example being MS, were once considered a form of hysteria (or whatever 'nicer' name they are using for that these days), and ours is kind of stuck there right now, but there's good research if you know where to look. If it's someone with patience, this can be well received. Some allied health professionals, even.