in its noun form, 'silly' refers to a foolish person. However, this usage is less common in modern English.
You're such a silly sometimes, always forgetting where you put your glasses.
Don't mind him; he's just a silly who loves to joke around.
using 'silly' as a noun can sound old-fashioned or overly informal in certain contexts.
as an adjective, 'silly' describes someone or something that is lacking in good sense, judgment, or is foolish. It can also refer to something light-hearted or not serious.
That was a silly mistake to make during the test.
She made a silly face to make the baby laugh.
It's just a silly rumor; don't pay attention to it.
'silly' can be endearing or derogatory based on context. For example, 'You're so silly!' can be affectionate, while 'Don't be silly!' might be dismissive.
'silly' can also be used as an adverb, though this is less common and might be considered colloquial or informal. In this form, it emphasizes the foolishness of an action.
You're acting silly again.
He laughed silly after hearing the joke.
this adverbial use of 'silly' is less standard and might not be appropriate for formal writing or speech.