diff --git a/Log.cpp b/Log.cpp
index 649c890..f11e26e 100644
--- a/Log.cpp
+++ b/Log.cpp
@@ -19,9 +19,9 @@ namespace Log {
 // abstract base class for a log sink
 class Output {
 public:
-	Output() {}
-	Output(Level lvl_max) : lvl_max(lvl_max) {}
-	virtual ~Output() {}
+	Output() = default;
+	explicit Output(Level lvl_max) : lvl_max{lvl_max} {}
+	virtual ~Output() = default;
 
 	virtual void log(Level lvl, std::stringbuf* sbuf) {
 		//aquire lock
@@ -52,7 +52,7 @@ protected:
 // logging to stdout/stderr
 class ConsoleOutput : public Output {
 public:
-	ConsoleOutput() : Output() {}
+	ConsoleOutput() = default;
 
 	virtual bool setColoredOutput(bool enabled) {
 		// TODO: check the terminal's compatibility for colors
@@ -137,13 +137,13 @@ void log(Level lvl, std::stringbuf* strb) {
 	}
 }
 
-LeveledSink fatal{Level::fatal};
-LeveledSink error{Level::error};
-LeveledSink warn{Level::warn};
-LeveledSink note{Level::note};
-LeveledSink info{Level::info};
-LeveledSink debug{Level::debug};
-LeveledSink trace{Level::trace};
+const LeveledSink fatal{Level::fatal};
+const LeveledSink error{Level::error};
+const LeveledSink warn{Level::warn};
+const LeveledSink note{Level::note};
+const LeveledSink info{Level::info};
+const LeveledSink debug{Level::debug};
+const LeveledSink trace{Level::trace};
 
 /*
  * class Entry
diff --git a/Log.h b/Log.h
index c196587..0527ff8 100644
--- a/Log.h
+++ b/Log.h
@@ -34,8 +34,11 @@ private:
 	void addMetadataHeader();
 
 public:
-	Entry(Level lvl);
+	explicit Entry(Level lvl);
+	Entry(const Entry&) = delete;
+	Entry& operator=(const Entry&) = delete;
 	Entry(Entry&&) = default;
+	Entry& operator=(Entry&&) = default;
 	~Entry();
 
 	Level getLevel() const {
@@ -60,9 +63,9 @@ private:
 	Level level;
 
 public:
-	LeveledSink(Level level) : level{level} {};
+	explicit LeveledSink(Level level) noexcept : level{level} {};
 
-	template <typename T> Entry operator<<(const T& msg) {
+	template <typename T> Entry operator<<(const T& msg) const {
 		Entry entry{level};
 		entry << msg;
 		return entry;
@@ -70,12 +73,12 @@ public:
 };
 
 // LeveledSinks
-extern LeveledSink fatal;
-extern LeveledSink error;
-extern LeveledSink warn;
-extern LeveledSink note;
-extern LeveledSink info;
-extern LeveledSink debug;
-extern LeveledSink trace;
+extern const LeveledSink fatal;
+extern const LeveledSink error;
+extern const LeveledSink warn;
+extern const LeveledSink note;
+extern const LeveledSink info;
+extern const LeveledSink debug;
+extern const LeveledSink trace;
 
 } // namespace Log