They would be a hypocrite.
A person who pretends a great deal about everything is often referred to as a "fabricator" or a "fraud." They may also be called a "deceiver" or a "charlatan."
A person who pretends to be what they are not is typically referred to as an impostor or a fraud.
Pretends to be ill is when a person is acting as if he/she is ill but actually the person is not ill.
imposter
nice...
foolish
A good person a nice sweet person
Innocent
yes actually well it depends on what you call nice
A double agent.
An individual who pretends to be knowledgeable in order to deceive is known as a charlatan. One who pretends to be knowledgeable or clever in general can be called a wiseacre.