|Origin:||rationalis, from ratio; RATIO|
rational thoughts, decisions etc are based on reasons rather than emotions [≠ irrational]:
Parents need to be fully informed so they can make a rational decision.
I'm sure there's a rational explanation for all this.
It's impossible to have a rational conversation with him.
a rational person is able to think calmly and sensibly [≠ irrational]:
Culley was quite rational at the time of her baby's death.
able to make sensible judgments:
Man is a rational animal.
We were too shocked to think rationally.
—rationality noun [uncountable]