1. Some of those goals may lead to thorny discussions.

2. One of the thorny problems these carriers are dealing with, like other organizations, is security.

3. As a Web programming language, PHP code can be particularly thorny to debug.

4. Over the next year, diplomats will attempt to hammer out the many outstanding thorny issues.

5. The issue is thorny, spurring a variety of suggestions for how to overhaul the visa program.