The best definition for succinct is Concise.
The Meriam-Webster official definition for succinct is "marked by compact precise expression without wasted words."
The Meriam-Webster official definition for concise is "marked by brevity of expression or statement: free from all elaboration and superfluous detail"
These two definitions, put simply, mean that you are not adding extra/unnecessary words to your statement, making sure to keep your main point clear.
I hope this helped!
I would appreciate it if you marked me as brainliest :-)
(I'm almost at the next rank, virtuoso!)