1) Nibble – to eat it slowly or show some inclination to accept offer

 If you nibble your chips chocolate and your sister gobble her quickly, you will last long.

 2) Noisome – having extremely and offensive smell

 Noisome vapours from the smouldering waste.

 3) Nonchalant – not having interest 

 Some people take her nonchalant attitude wrong way.

 4) Nonplussed – greatly surprised 

 If someone conversation leaves you scratching your mind what they were talkin then you were nonplussed.

 5) Nostrum – ineffective

 You are suffering from cold and you tried medicine which claim they can cure your cold but nothing work, they are nostrum medicines.

 6) Noxious – Harmful even fatal

 Noxious gasses

 7) Nugatory – no real value

 All of your excuses are nugatory.

 8) Nihilism – rejecting all religions and moral principles in the belief that life is meaningless