After
neither of+noun/pronoun ,we use a singular verb in a formal style.
-Neither of my sisters is married.
In an informal style,you can use a plural verb.
-Neither of my sisters are married.
And your question:Neither can be used alone without a noun or pronoun ,if the meaning is clear.Here neither is used instead of 'neither of them' and as I said,in a formal style a singular verb is proper.