cogent
Meaning: intellectually convincing
Usage: Irene’s arguments in favor of abstinence were so cogent that I could not resist them.
coherent
Meaning: logically consistent, intelligible
Usage: Renee could not figure out what Monroe had seen because he was too distraught to deliver a coherent statement.
cohesive
Meaning: unified and holding together well
Usage: The team gave a cohesive presentation with each part connected clearly.
consistent
Meaning: not contradictory; steady or reliable
Usage: Her explanation was consistent with the evidence in the report.
logical
Meaning: reasonable and based on sound thinking
Usage: The student offered a logical solution to the scheduling problem.