diff --git a/src/uvw/util.hpp b/src/uvw/util.hpp
index 424ae14c..c8a7cfde 100644
--- a/src/uvw/util.hpp
+++ b/src/uvw/util.hpp
@@ -36,7 +36,7 @@ public:
     constexpr Flags operator&(const Flags& f) const noexcept { return Flags(flags & f.flags); }
     constexpr Flags operator&(E flag) const noexcept { return Flags(flags & toInnerType(flag)); }
 
-    constexpr operator bool() const noexcept { return !(flags == InnerType{}); }
+    explicit constexpr operator bool() const noexcept { return !(flags == InnerType{}); }
     constexpr operator Type() const noexcept { return flags; }
 
 private: