semilethal
/ˌsɛmiˈliθəl/
adjective
- Causing death in some but not all cases; partly lethal.
- The virus was semilethal, proving fatal for some patients while others recovered fully.
- The semilethal mutation killed half of the fruit flies in the experiment.
- Farmers must watch for semilethal plant diseases that can wipe out a portion of the crop.