superl severe; violent; as, a tough storm.
2. tough ·superl stiff; rigid; not flexible; stubborn; as, a tough bow.
3. tough ·superl not easily separated; viscous; clammy; tenacious; as, tough phlegm.
4. tough ·superl not easily broken; able to endure hardship; firm; strong; as, tough sinews.
5. tough ·superl having the quality of flexibility without brittleness; yielding to force without breaking; capable of resisting great strain; as, the ligaments of animals are remarkably tough.