ANSWERS

1. Khartoum

2. Clowns

3. Libel is written, whereas slander is spoken

4. Bolshoi

5. A sand or dust storm

6. Microwave oven

7. Piano builders or pianos

8. Seven answers: 
    a: Zeitgeist (lit; the trend at that time), 
    b: Wicker (such as in basketry), 
    c: Ombudsman, 
    d: Gesundheit, 
    e: Smorgasbord, 
    f: Sputnik, 
    g: Pavlova (Anna Pavlova)

9. Mummy

10. Virus

11. The devil (Satan, Lucifer etc)

12. Automobiles

13. Sampan