1. An explanation that is doubtful, unclear, or open to doubt regarding its validity, credibility, or truthfulness
His explanation for missing the meeting was questionable at best.
Sua explicação para ter faltado à reunião era no mínimo questionável.
2. A reason or account that lacks sufficient evidence or logical support
The scientist's questionable explanation was rejected by the peer review panel.
A explicação questionável do cientista foi rejeitada pelo painel de revisão por pares.