diff --git a/opter.js b/opter.js
index 5591aac..bc83b21 100644
--- a/opter.js
+++ b/opter.js
@@ -51,8 +51,8 @@ module.exports = class Opts {
     const name = stripDashes(nameWithDashes);
     if (name in this.opts) return true;
     if (name in this.synonyms) {
-      let syns = this.synonyms[name];
-      let hits = syns.filter(s => s in this.opts ).length;
+      const syns = this.synonyms[name];
+      const hits = syns.filter(s => s in this.opts ).length;
       if (hits > 0) { return true; }
     }
     throw new Error(errorMessage || defaultErrorMessages.missingRequiredOption(nameWithDashes));
@@ -94,7 +94,11 @@ module.exports = class Opts {
   contains(nameWithDashes) {
     const name = stripDashes(nameWithDashes);
     if (name in this.opts) return true;
-    if (name in this.synonyms) return true; // FIXME
+    if (name in this.synonyms) {
+      const syns = this.synonyms[name];
+      const hits = syns.filter(s => s in this.opts ).length;
+      if (hits > 0) { return true; }
+    }
     return false;
   }
 }