Synonyms for Rational (same or very similar meaning)
WordNet sense 1 (an integer or a fraction):
rational number
WordNet sense 2 (marked by sound judgment):
reasonable, sane
WordNet sense 3 (endowed with the capacity to reason):
intelligent, reasoning, thinking
WordNet sense 4 (capable of thinking and expressing yourself in a clear and consistent manner):
logical, lucid
WordNet sense 5 (of or associated with or requiring the use of the mind):
noetic
WordNet sense 6 (involving the mind or an intellectual process):
mental
WordNet sense 7 (appealing to or using the intellect):
intellectual
From the ODE community, based on WordNet
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