To identify the correct synonym for "redoubtable", we first define its meaning.
"Redoubtable" describes a person or thing as formidable, particularly as an adversary, evoking fear or admiration due to significant power, skill, or prominence.
Next, we examine each option:
- Flimsy: Signifies a lack of solidity or strength, the direct antonym of formidable, and therefore not a synonym.
- Perplexing: Implies confusion or bewilderment, which does not correspond to the characteristic of being formidable.
- Formidable: This term directly corresponds to the meaning of "redoubtable," as both denote something that commands respect or fear.
- Voluble: Pertains to speaking fluently and incessantly, unrelated to the concept of inspiring fear or respect.
Consequently, the accurate synonym for "redoubtable" is formidable.