The phrase "terrible disease" means a very bad and harmful sickness or illness that can cause a lot of suffering and difficulties for someone who has it. Full definition
There are terrible diseases like multiple sclerosis, diabetes, all forms of cancer and so on. (customcollegeessays.com)
So don't be surprised when we recommend dental work for your pet even if you can't see terrible disease. (sunnysidevetclinic.com)
The results could have implications for the aging population that's struggling with the problem of terrible diseases like Alzheimer's and dementia. (ahealthblog.com)