1.
A ~ illness or disability is one that severely damages your health or your body.
Arthritis and rheumatism are prominent ~ diseases...
ADJ: ADJ n
2.
If you say that an action, policy, or situation has a ~ effect on something, you mean it has a very serious, harmful effect.
The high cost of capital has a ~ effect on many small American high-tech firms...
ADJ: usu ADJ n