Across
- 1. underground train or its path or system
- 2. relating the layer just beneath the skin
- 3. an expression that uses exaggeration
- 4. the best, highest, or greatest
- 5. difficult to detect
- 6. abnormally or extremely busy or engaged
- 7. not existing within the physical order
- 8. severely low body temperature
Down
- 1. to put completely under water
- 4. a ship that operates underwater