Although nephrite is less hard than jadeite on this scale, the tight felting of its fibrous crystals makes it exceptionally tough.

Export of technology with both civilian and military applications poses an exceptionally tough problem for arms control.

Now Rockefeller Center's management is considering expanding yet again, and they are faced with an exceptionally tough design problem.

Small and not exceptionally tough, they had been crushed by two offenses, one of which is mediocre at best.

Connecticut, making its 12th straight tournament appearance, drew an exceptionally tough bracket.

On the way out of the country he was, like everybody else, subjected to the exceptionally tough security checks.

The A-10 is exceptionally tough.

Today she is well known as an exceptionally tough customer in an industry where ruthless business dealings are considered the norm.

He was always a weak candidate in an exceptionally tough year.