2 : 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"
3 : of a stern or strict bearing or demeanor; forbidding in aspect; "an austere expression"; "a stern face"
4 : unfortunate or hard to bear; "had hard luck"; "a tough break"
5 : 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"
