So, am I correct in thinking that "mgonjwa" means "patient," and "ugonjwa" means "illness or disease?"
To quote one of our contributors: yup!
I recommend this on-line dictionary: http://www.elimuyetu.co.tz/subjects/arts/swa-eng/
Ugonjwa ni suna kufa faradhi: 'Illness is optional but death is inevitable'
I tried the link you provided but got the following message:
You don't have permission to access /subjects/arts/swa-eng/ on this server.
OK, don't know what happened. These work: