severe in WordNet English dictionary

1. severely simple
   "a stark interior"
   austere  severe  stark  stern 
   
2. causing fear or anxiety by threatening great harm
   "a dangerous operation"; "a grave situation"; "a grave illness"; "grievous bodily harm"; "a serious wound"; "a serious turn of events"; "a severe case of pneumonia"; "a life-threatening disease"
   dangerous  grave  grievous  serious  severe  life-threatening 
   
3. very strong or vigorous
   "strong winds"; "a hard left to the chin"; "a knockout punch"; "a severe blow"
   hard  knockout  severe 
   
4. intensely or extremely bad or unpleasant in degree or quality
   "severe pain"; "a severe case of flu"; "a terrible cough"; "under wicked fire from the enemy's guns"; "a wicked cough"
   severe  terrible  wicked 
   
5. very bad in degree or extent
   "a severe worldwide depression"; "the house suffered severe damage"
   severe 
   
6. unsparing and uncompromising in discipline or judgment
   "a parent severe to the pitch of hostility"- H.G.Wells; "a hefty six-footer with a rather severe mien"; "a strict disciplinarian"; "a Spartan upbringing"
   severe  spartan