diff --git a/compris/PreferredAlternatives.yml b/compris/PreferredAlternatives.yml
new file mode 100644
index 0000000..39ca3dd
--- /dev/null
+++ b/compris/PreferredAlternatives.yml
@@ -0,0 +1,8 @@
+extends: substitution
+message: "Prefer '%s' over '%s'."
+level: warning
+ignorecase: true
+action:
+  name: replace
+swap:
+  0-day: zero-day
diff --git a/fixtures/PreferredAlternatives/.vale.ini b/fixtures/PreferredAlternatives/.vale.ini
new file mode 100644
index 0000000..d0f9b8d
--- /dev/null
+++ b/fixtures/PreferredAlternatives/.vale.ini
@@ -0,0 +1,6 @@
+StylesPath = ../../
+
+MinAlertLevel = suggestion
+
+[*.md]
+compris.PreferredAlternatives = YES
diff --git a/fixtures/PreferredAlternatives/test.md b/fixtures/PreferredAlternatives/test.md
new file mode 100644
index 0000000..e4db2dd
--- /dev/null
+++ b/fixtures/PreferredAlternatives/test.md
@@ -0,0 +1,4 @@
+# Preferred Alternatives
+
+<!-- 0-day -->
+A hacker forum was found selling a 0-day exploit for a popular web browser.
diff --git a/test/expectations/PreferredAlternatives.log b/test/expectations/PreferredAlternatives.log
new file mode 100644
index 0000000..4a3e846
--- /dev/null
+++ b/test/expectations/PreferredAlternatives.log
@@ -0,0 +1 @@
+test.md:4:36:compris.PreferredAlternatives:Prefer 'Zero-day' over '0-day'.