Able to be supported by reasons or evidence, though not certainly proven or universally accepted.
From argue (Latin arguere, 'to make clear, prove') plus the suffix -able meaning 'capable of being.' The Latin root meant 'to make clear' before it evolved to mean 'to dispute.'
Arguable is the diplomatic word for 'you might have a point, but I'm not convinced yet'—it's how scientists and philosophers protect themselves while still taking ideas seriously.
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