Write a definition, the part of speech and an original sentence for the following list of vocabulary words.
1. abet
2. alluvium
3. beatify
4. cadence
5. coalescence
6. demagogue
7. emeritus
8. foppish
9. grotto
10. humbug
11. insidious
12. jocose
13. knavery
14. lien
15. malefactor
16. nettle
17. osculate
18. palinode
19. rife
20. tyro