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.