BITSAT 2019 Slot 2 Solved Paper

Cogent (Adjective), which means reasonable and convincing. The correct antonym will be ‘dissuasive’, which means divert from the measure or purpose.
Antonyms Unconvincing, muddle, vague
Synonyms Convincing, logical, compelling.
e.g. He put forward some cogent reasons for initiating the project.