A script that add the saved status to the Word of the Day page so you don't have to click on the "See the entry" link, thus saving you a few precious seconds

Merriam-WebsterHelper.js

// ==UserScript==
// @name         Merriam-Webster Helper
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  A tiny script that makes merriam-webster.com/ work nicely with Vimium, namely, it removes the focus from the search bar so that you can use the vim commands to move around.
// @author       Rafael Rendon Pablo
// @run-at       document-idle
// @match        https://www.merriam-webster.com/
// @match        https://www.merriam-webster.com/word-of-the-day
// @match        https://www.merriam-webster.com/word-of-the-day/*
// @match        https://www.merriam-webster.com/dictionary/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=merriam-webster.com
// @grant        GM_xmlhttpRequest
// ==/UserScript==

(function() {
    'use strict';

    // Merriam-Websters' search form gets focused every time a tab becomes visible,
    // this interferes with Vimium.

    // Remove the focus when the page loads
    const searchButton = document.getElementsByClassName('btn position-absolute search-button search-dictionary');
    if (searchButton.length > 0) {
        console.log("Removing focus from search form")
        document.activeElement.blur();
    }

    // Remove the focus when the page regains visibility
    document.addEventListener("visibilitychange", function() {
        if (!document.hidden){
            console.log("Browser tab is visible, removing focus from search form")
            document.activeElement.blur();
        }
    });

    const wordElement = document.querySelectorAll('div.word-and-pronunciation h2');
    if (wordElement.length === 0) {
        return
    }
    console.log("On Word of the Day page")
    const word = wordElement[0].textContent;
    const wordAttributes = document.querySelectorAll('div.word-attributes');


    const copyURLButton = document.createElement('button');
    copyURLButton.append('Copy URL');
    copyURLButton.addEventListener('click', function () {
        const url = window.location.href.toString();
        navigator.clipboard.write([
                new ClipboardItem({
                    'text/plain': new Blob([url],
                        {type: 'text/plain'}
                    ),
                    'text/html': new Blob(
                        ['<a href="' + url + '">' + url + '</a>'],
                        {type: 'text/html'},
                    ),
                }),
            ]).then(() => {
                console.log("Copied URL to the clipboard: " + url);
            }).catch((err) => {
                console.error("Failed to copy URL to the clipboard: " + err);
            });
    });

    const copyURL = document.createElement('span');
    copyURL.append(copyURLButton);
    wordAttributes[0].append(copyURL);

    const wordStatus = document.createElement('span');
    wordStatus.setAttribute('class', 'word-syllables');
    wordAttributes[0].append(wordStatus);

    const savedLabel = document.createElement('span');
    savedLabel.append('SAVED');
    const getDefinition = function(url, callback) {
    };

    const handleSaveResponse = function(response) {
        const data = JSON.parse(response.responseText);
        if (data.status === 'success') {
            wordStatus.removeChild(saveButton);
            wordStatus.append(savedLabel);
            console.log("Saved word successfully");
        } else {
            console.error("Unable to save word");
        }
    };

    const saveButton = document.createElement('button');
    saveButton.append('Save');
    saveButton.addEventListener('click', function () {
        GM_xmlhttpRequest({
            method: 'POST',
            url: 'https://www.merriam-webster.com/lapi/v1/wordlist/save',
            onload: handleSaveResponse,
            data: 'word=' + word + '&type=d',
            headers: {
                'Accept': 'application/json, text/javascript, */*; q=0.01',
                'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8',
            },
        });
    });

    const handleIsSavedResponse = function(response) {
        const isSaved = JSON.parse(response.responseText).data.data.saved;
        if (isSaved) {
            wordStatus.append(savedLabel);
        } else {
            wordStatus.append(saveButton);
        }
    };
    GM_xmlhttpRequest({
        method: 'GET',
        url: 'https://www.merriam-webster.com/lapi/v1/wordlist/is-saved?word=' + word + '&type=d',
        onload: handleIsSavedResponse
    });
})();