Learner's definition of SEVERE
[or more severe; most severe]
1 a : very bad, serious, or unpleasant
b : causing a lot of physical pain or suffering
severe weather conditions
The storm caused severe damage to the roof.
a severe economic depression
The patient is in severe pain.
children with severe learning disabilities
In the most severe cases, the disease can lead to blindness.
3 : requiring great effort 4 : very formal, strict, and serious 5 : not having much decoration : very plain