There are multiple definitions - click on the translation that matches your context.

manifestação da intenção de não cumprimento

substantivo

full

repudiation

noun

Definitions of repudiation

English

the refusal to accept, or the act of no longer accepting, a duty or an obligation

It would not entitle the buyer to reject all other instalments unless the seller's breach was so serious as to amount to a repudiation of the contract.