Fluent or persuasive in speaking or writing. (Oxford Dictionaries)
Clearly expressing or indicating something. (Oxford Dictionaries)
Speech or writing that is eloquent is well expressed and effective in persuading people. (Collins Dictionary)
A person who is eloquent is good at speaking and able to persuade people. (Collins Dictionary)
Marked by forceful and fluent expression. (Merriam – Webster)
Vividly or movingly expressive or revealing. (Merriam – Webster)
Giving a clear, strong message: (Cambridge Dictionary)
Five Writing Tips to Sound More Eloquent.
How to be eloquent.