We check this website, now merriam-webster.com is up and dont blocked for our system and other users of the Internet.
So, answer to question: Is merriam-webster Down Right Now? - NO! merriam-webster is up!
If you have problem with access to site merriam-webster, and domain merriam-webster.com is not avalible.
Clear browser cache and/or try other web browser
(Chrome, Firefox or Safari).