1. Erinaceous
Like a hedgehog

2. Lamprophony
Loudness and clarity of voice

3. Depone
To testify under oath

4. Finnimbrun
A trinket or knick-knack

5. floccinaucinihilipilification
Estimation that something is valueless. Proper pronunciation based on Latin roots: flockə-nowsə-nəkələ-pələ-fək-ation.

6. Inaniloquent
Pertaining to idle talk

7. Limerance
An attempt at a scientific study into the nature of romantic love.

8. Mesonoxian
Pertaining to midnight

9. Mungo
A dumpster diver – one who extracts valuable things from trash

10. Nihilarian
A person who deals with things lacking importance (pronounce the ‘h’ like a ‘k’).

11. Nudiustertian
The day before yesterday

12. Phenakism
Deception or trickery

13. Pronk
A weak or foolish person

14. Pulveratricious
Covered with dust

15. Rastaquouere
A social climber

16. Scopperloit
Rude or rough play

17. Selcouth
Unfamiliar, rare, strange, marvelous, wonderful. For example: The List Universe is such a selcouth website!

18. Tyrotoxism
To be poisoned by cheese

19. Widdiful
Someone who deserves to be hanged

20. Zabernism
The abuse of military power or authority. I wonder how long it will take for this one to show up in the comments.