1. An unplanned or spontaneous addition or supplement made without prior preparation, typically to a document, speech, or planned activity
The speaker made an improvised addendum to address the unexpected question from the audience.
O palestrante fez um adendo improvisado para responder à pergunta inesperada do público.
2. A hastily added clause, amendment, or extra content inserted extemporaneously
The contract included several improvised addendums that were handwritten in the margins.
O contrato incluía vários adendos improvisados que foram escritos à mão nas margens.