From their FAQ, about account deletion:
You can cancel your subscription by logging in to the My Account page and selecting the Cancel My Subscription option or by writing to Member Support: [email protected].
Besides, from their PP: to correct, update, or remove personally identifiable information, please email us at [email protected].
However, and as usual, you should note:
We retain your information for as long as necessary to permit us to use it for the purposes that we have communicated to you and comply with applicable law or regulations.
URLS:
http://www.merriam-webster.com/
Please note that AccountKiller.com is not associated with the business listed on this page. AccountKiller provides easy-to-understand instructions and guides on how to cancel charges and relationships from the list of businesses on our site, we have no affiliation with these businesses.