Definition from Wiktionary, the free dictionary
faster-than-light (not comparable)
- Faster than the speed of light in a vacuum, the theoretical speed limit for travel within the universe.
Usage notes 
- This is the form used before a noun. After a noun, the form used is faster than light:
- The laws of physics forbid faster-than-light travel.
- Tachyons travel at speeds faster than light.