diff --git a/ext/bg/js/handlebars.js b/ext/bg/js/handlebars.js
index 66d5fa2b..72908cab 100644
--- a/ext/bg/js/handlebars.js
+++ b/ext/bg/js/handlebars.js
@@ -75,6 +75,18 @@ function handlebarsMultiLine(options) {
     return options.fn(this).split('\n').join('<br>');
 }
 
+function handlebarsTermFrequencyColor(options) {
+    const termFrequency = options.fn(this);
+
+    if (termFrequency === 'popular') {
+        return '#0275d8';
+    } else if (termFrequency === 'rare') {
+        return '#999';
+    } else {
+        return 'inherit';
+    }
+}
+
 function handlebarsRegisterHelpers() {
     if (Handlebars.partials !== Handlebars.templates) {
         Handlebars.partials = Handlebars.templates;
@@ -83,6 +95,7 @@ function handlebarsRegisterHelpers() {
         Handlebars.registerHelper('furiganaPlain', handlebarsFuriganaPlain);
         Handlebars.registerHelper('kanjiLinks', handlebarsKanjiLinks);
         Handlebars.registerHelper('multiLine', handlebarsMultiLine);
+        Handlebars.registerHelper('termFrequencyColor', handlebarsTermFrequencyColor);
     }
 }
 
diff --git a/ext/bg/js/options.js b/ext/bg/js/options.js
index 5902bc30..475a5e66 100644
--- a/ext/bg/js/options.js
+++ b/ext/bg/js/options.js
@@ -79,7 +79,7 @@ function optionsFieldTemplates() {
 {{#*inline "furigana"}}
     {{~#if merge~}}
         {{~#each definition.expressions~}}
-            {{~#furigana}}{{{.}}}{{/furigana~}}
+            <span style="color: {{#termFrequencyColor}}{{termFrequency}}{{/termFrequencyColor}}">{{~#furigana}}{{{.}}}{{/furigana~}}</span>
             {{~#unless @last}}、{{/unless~}}
         {{~/each~}}
     {{~else~}}