This is the 1999th most frequent Portuguese word.
assinado
Signed.
In this sentence, 'assinado' is used as a past participle, describing an action that was performed, specifically the signing of the document.
O documento foi assinado pelo diretor.
The document was signed by the director.
Here, 'assinado' functions within a past perfect tense to describe a completed action that preceded another past action.
Eu já havia assinado o contrato antes de sair.
I had already signed the contract before leaving.
In this context, 'assinado' acts as an adjective describing the current state of the form.