severe

adjective

1. intensely or extremely bad or unpleasant in degree or quality"severe pain"
2. very strong or vigorous"a hard left to the chin"
3. severely simple"a stark interior"
4. unsparing and uncompromising in discipline or judgment"a parent severe to the pitch of hostility"
5. causing fear or anxiety by threatening great harm"a dangerous operation"
6. very bad in degree or extent"a severe worldwide depression"