This is the 2264th most frequent Portuguese word.
válida
"Válida" means "valid" in English.
In this sentence, 'válida' is used as an adjective to qualify 'ideia', indicating the idea's suitability or soundness.
Esta é uma ideia válida para resolver o problema.
This is a valid idea to solve the problem.
Here, 'válida' serves as an adjective describing 'assinatura do contrato', emphasizing that the signature's validity depends on agreement by both sides.
A assinatura do contrato só será válida após ambas as partes concordarem.
The contract signature will only be valid after both parties agree.
In this context, 'válida' is an adjective modifying 'explicação', suggesting that the explanation sought must be reasonable and credible.