Dictionary.net

a cruel and brutal fellow

very difficult; severely testing stamina or resolution; "a rugged competitive examination"; "the rugged conditions of frontier life"; "the competition was tough"; "it's a tough life"; "it was a tough job"

someone who learned to fight in the streets rather than being formally trained in the sport of boxing

unfortunate or hard to bear; "had hard luck"; "a tough break"

tough to cut or chew

feeling physical discomfort or pain (`tough' is occasionally used colloquially for `bad'); "my throat feels bad"; "she felt bad all over"; "he was feeling tough after a restless night"

not given to gentleness or sentimentality; "a tough character"

a cruel and brutal fellow

very difficult; severely testing stamina or resolution; "a rugged competitive examination"; "the rugged conditions of frontier life"; "the competition was tough"; "it's a tough life"; "it was a tough job"

someone who learned to fight in the streets rather than being formally trained in the sport of boxing

unfortunate or hard to bear; "had hard luck"; "a tough break"

tough to cut or chew

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.

Not easily broken; able to endure hardship; firm; strong; as, tough sinews.

Not easily separated; viscous; clammy; tenacious; as, tough phlegm.

Stiff; rigid; not flexible; stubborn; as, a tough bow.

Severe; violent; as, a tough storm.

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.

Not easily broken; able to endure hardship; firm; strong; as, tough sinews.

Not easily separated; viscous; clammy; tenacious; as, tough phlegm.

Stiff; rigid; not flexible; stubborn; as, a tough bow.

Severe; violent; as, a tough storm.

Colloquially, a rough fellow; a rowdy.

Toughly.

Toughness.

Toughly.

Toughness.

Not easily broken: firm: stiff: sticky: tenacious: able to endure hardship.

Not easily broken; tenacious; strong; able to endure hardship.

Admitting of tugging and pulling without fracture or injury; not easily broken or separated; able to endure hardships; tenacious; difficult, as a tough piece of business.