Question

Can the introduction take this form -
First of all, what is cleanliness?
According to Miriam Webster's dictionary, cleanliness is the property of being habitually clean and having good hygiene. Cleanliness has a lot to do with safe and healthy living

Answer 1

This is the correct definition of "cleanliness"

Answer 2

So does this mean the introduction is acceptable

Answer 3

There's no way to tell unless you have already written the rest of the paper. Read and follow directions here:
http://lklivingston.tripod.com/essay/
Notice that the introduction is not to be written first.