Silly is used to relate to something that is characterized by weakness or folly. Anything devoid of common understanding or judgment is termed as silly.
It is quite often used to refer to a person who is weak in intellect, plain or simple, witless or foolish. In still more lay man terms silly means exhibiting lack of wisdom or good sense. It means more or less the same as foolish. In the words of Rose Franken, “Anyone can be passionate, but it takes real lovers to be silly.” Something that is silly may not always be absurd, yes, it may be frivolous but the intentions behind the same need not necessarily be inappropriate. Just like most comic characters do silly things guided by you would say ‘childish behaviour’ but their prime motive is to catch the attention of the minor audiences. In the words of Mary Worley, “A man that is ashamed of passions that are natural and reasonable is generally proud of those that are shameful and silly.”