Frequency: The word is one of the 700 most common words in English.
1.
You use perhaps to express uncertainty, for example, when you do not know that something is definitely true, or when you are mentioning something that may possibly happen in the future in the way you describe.
Millson regarded her thoughtfully. Perhaps she was right...
In the end they lose millions, perhaps billions...
It was bulky, perhaps three feet long and almost as high...
Perhaps, in time, the message will get through...
They'd come soon, perhaps when the radio broadcast was over.
= maybe
ADV: ADV with cl/group [vagueness]
2.
You use perhaps in opinions and remarks to make them appear less definite or more polite.
Perhaps the most important lesson to be learned is that you simply cannot please everyone...
His very last paintings are perhaps the most puzzling...
Do you perhaps disapprove of Agatha Christie and her Poirot and Miss Marple?...
ADV: ADV with cl/group [vagueness]
3.
You use perhaps when you are making suggestions or giving advice. Perhaps is also used in formal English to introduce requests.
Perhaps I may be permitted a few suggestions...
Well, perhaps you'll come and see us at our place?...
ADV: ADV with cl [politeness]
4.
You can say perhaps as a response to a question or remark, when you do not want to agree or accept, but think that it would be rude to disagree or refuse.
'I'm sure we can make it,' he says. Perhaps, but it will not be easy.
ADV: ADV as reply