diff --git a/shared/editor/commands/toggleMark.ts b/shared/editor/commands/toggleMark.ts
index d67b2fc2be..376ffc648f 100644
--- a/shared/editor/commands/toggleMark.ts
+++ b/shared/editor/commands/toggleMark.ts
@@ -1,24 +1,120 @@
 import { toggleMark as pmToggleMark } from "prosemirror-commands";
 import type { MarkType } from "prosemirror-model";
-import type { Command } from "prosemirror-state";
+import type { Command, EditorState } from "prosemirror-state";
+import { TextSelection } from "prosemirror-state";
 import type { Primitive } from "utility-types";
 import { chainTransactions } from "../lib/chainTransactions";
+import { getMarksBetween } from "../queries/getMarksBetween";
 import { isMarkActive } from "../queries/isMarkActive";
 
+const wordCharRegex = /[\p{L}\p{N}_]/u;
+
+const ATOM_PLACEHOLDER = "";
+
+/**
+ * If the selection is an empty cursor sitting inside a word (with word
+ * characters on both sides) in a textblock that allows the given mark type,
+ * returns the document positions spanning that word. Returns null otherwise —
+ * including when the cursor is at the leading or trailing edge of a word,
+ * since intent is ambiguous in those cases.
+ */
+function findWordRangeAtCursor(
+  state: EditorState,
+  type: MarkType
+): { from: number; to: number } | null {
+  const { selection } = state;
+  if (!(selection instanceof TextSelection)) {
+    return null;
+  }
+  const $cursor = selection.$cursor;
+  if (!$cursor || !$cursor.parent.isTextblock) {
+    return null;
+  }
+  if (!$cursor.parent.type.allowsMarkType(type)) {
+    return null;
+  }
+
+  const parentStart = $cursor.start();
+  const parentEnd = $cursor.end();
+  const text = state.doc.textBetween(
+    parentStart,
+    parentEnd,
+    undefined,
+    ATOM_PLACEHOLDER
+  );
+  const offset = $cursor.pos - parentStart;
+
+  const before = offset > 0 ? text[offset - 1] : "";
+  const after = offset < text.length ? text[offset] : "";
+  if (!wordCharRegex.test(before) || !wordCharRegex.test(after)) {
+    return null;
+  }
+
+  let start = offset;
+  let end = offset;
+  while (start > 0 && wordCharRegex.test(text[start - 1])) {
+    start--;
+  }
+  while (end < text.length && wordCharRegex.test(text[end])) {
+    end++;
+  }
+
+  return { from: parentStart + start, to: parentStart + end };
+}
+
+function rangeHasMarkWithAttrs(
+  state: EditorState,
+  type: MarkType,
+  attrs: Record<string, Primitive> | undefined,
+  from: number,
+  to: number
+): boolean {
+  if (!state.doc.rangeHasMark(from, to, type)) {
+    return false;
+  }
+  if (!attrs) {
+    return true;
+  }
+  return getMarksBetween(from, to, state).some(
+    ({ mark }) =>
+      mark.type === type &&
+      Object.keys(attrs).every((key) => mark.attrs[key] === attrs[key])
+  );
+}
+
 /**
  * Toggles a mark on the current selection, if the mark is already with
  * matching attributes it will remove the mark instead, if the mark is active
  * but with different attributes it will update the mark with the new attributes.
  *
+ * When invoked with an empty cursor sitting inside a word (with word
+ * characters on both sides), the mark is applied to that whole word without
+ * altering the user's selection.
+ *
  * @param type - The mark type to toggle.
  * @param attrs - The attributes to apply to the mark.
  * @returns A prosemirror command.
  */
 export function toggleMark(
   type: MarkType,
-  attrs: Record<string, Primitive> | undefined
+  attrs?: Record<string, Primitive>
 ): Command {
   return (state, dispatch) => {
+    const wordRange = findWordRangeAtCursor(state, type);
+    if (wordRange) {
+      const { from, to } = wordRange;
+      const hasMatching = rangeHasMarkWithAttrs(state, type, attrs, from, to);
+
+      if (dispatch) {
+        const tr = state.tr.removeMark(from, to, type);
+        if (!hasMatching) {
+          tr.addMark(from, to, type.create(attrs));
+        }
+        dispatch(tr);
+      }
+      return true;
+    }
+
     if (isMarkActive(type, attrs)(state)) {
       return pmToggleMark(type)(state, dispatch);
     }
diff --git a/shared/editor/marks/Bold.ts b/shared/editor/marks/Bold.ts
index f585bffce3..b7d4d30420 100644
--- a/shared/editor/marks/Bold.ts
+++ b/shared/editor/marks/Bold.ts
@@ -1,6 +1,6 @@
-import { toggleMark } from "prosemirror-commands";
 import type { InputRule } from "prosemirror-inputrules";
 import type { MarkSpec, MarkType } from "prosemirror-model";
+import { toggleMark } from "../commands/toggleMark";
 import { markInputRuleForPattern } from "../lib/markInputRule";
 import Mark from "./Mark";
 
diff --git a/shared/editor/marks/Code.ts b/shared/editor/marks/Code.ts
index b296143f6f..68ed70c1f7 100644
--- a/shared/editor/marks/Code.ts
+++ b/shared/editor/marks/Code.ts
@@ -1,5 +1,4 @@
 import codemark from "prosemirror-codemark";
-import { toggleMark } from "prosemirror-commands";
 import type {
   MarkSpec,
   MarkType,
@@ -9,6 +8,7 @@ import type {
 } from "prosemirror-model";
 import { Plugin, TextSelection } from "prosemirror-state";
 import type { EditorView } from "prosemirror-view";
+import { toggleMark } from "../commands/toggleMark";
 import { markInputRuleForPattern } from "../lib/markInputRule";
 import type { MarkdownSerializerState } from "../lib/markdown/serializer";
 import { isInCode } from "../queries/isInCode";
diff --git a/shared/editor/marks/Highlight.ts b/shared/editor/marks/Highlight.ts
index 654706f2fc..a96be19f78 100644
--- a/shared/editor/marks/Highlight.ts
+++ b/shared/editor/marks/Highlight.ts
@@ -1,7 +1,7 @@
 import { isHexColor } from "class-validator";
 import { parseToRgb, rgba } from "polished";
-import { toggleMark } from "prosemirror-commands";
 import type { MarkSpec, MarkType } from "prosemirror-model";
+import { toggleMark } from "../commands/toggleMark";
 import { markInputRuleForPattern } from "../lib/markInputRule";
 import markRule from "../rules/mark";
 import Mark from "./Mark";
diff --git a/shared/editor/marks/Italic.ts b/shared/editor/marks/Italic.ts
index e5f25cafc9..c76c952cd3 100644
--- a/shared/editor/marks/Italic.ts
+++ b/shared/editor/marks/Italic.ts
@@ -1,7 +1,7 @@
-import { toggleMark } from "prosemirror-commands";
 import type { InputRule } from "prosemirror-inputrules";
 import type { MarkSpec, MarkType } from "prosemirror-model";
 import type { Command } from "prosemirror-state";
+import { toggleMark } from "../commands/toggleMark";
 import { markInputRuleForPattern } from "../lib/markInputRule";
 import Mark from "./Mark";
 
diff --git a/shared/editor/marks/Strikethrough.ts b/shared/editor/marks/Strikethrough.ts
index 58b12ae5e8..e4eddcc99c 100644
--- a/shared/editor/marks/Strikethrough.ts
+++ b/shared/editor/marks/Strikethrough.ts
@@ -1,5 +1,5 @@
-import { toggleMark } from "prosemirror-commands";
 import type { MarkSpec, MarkType } from "prosemirror-model";
+import { toggleMark } from "../commands/toggleMark";
 import { markInputRuleForPattern } from "../lib/markInputRule";
 import Mark from "./Mark";
 
diff --git a/shared/editor/marks/Underline.ts b/shared/editor/marks/Underline.ts
index 5e93378b59..4026a11df7 100644
--- a/shared/editor/marks/Underline.ts
+++ b/shared/editor/marks/Underline.ts
@@ -1,5 +1,5 @@
-import { toggleMark } from "prosemirror-commands";
 import type { MarkSpec, MarkType } from "prosemirror-model";
+import { toggleMark } from "../commands/toggleMark";
 import { markInputRuleForPattern } from "../lib/markInputRule";
 import underlinesRule from "../rules/underlines";
 import Mark from "./Mark";