coherent
US /koʊˈhɪr.ənt/
UK /koʊˈhɪr.ənt/

1.
logical and consistent; able to be understood
:
•
He presented a coherent argument that was easy to follow.
•
The witness's story was not entirely coherent.
2.
(of a person) able to speak clearly and logically
:
•
After the accident, he was barely coherent.
•
She was too upset to be fully coherent.