diff --git a/contrib/boost-cmake/CMakeLists.txt b/contrib/boost-cmake/CMakeLists.txt
index d00179f13cd..675931d319f 100644
--- a/contrib/boost-cmake/CMakeLists.txt
+++ b/contrib/boost-cmake/CMakeLists.txt
@@ -236,5 +236,6 @@ if (NOT EXTERNAL_BOOST_FOUND)
     add_library (_boost_graph ${SRCS_GRAPH})
     add_library (boost::graph ALIAS _boost_graph)
     target_include_directories (_boost_graph PRIVATE ${LIBRARY_DIR})
+    target_link_libraries(_boost_graph PRIVATE _boost_regex)
 
 endif ()
diff --git a/src/Functions/lemmatize.cpp b/src/Functions/lemmatize.cpp
index bee37594f4c..704d5f87575 100644
--- a/src/Functions/lemmatize.cpp
+++ b/src/Functions/lemmatize.cpp
@@ -4,7 +4,7 @@
 #include <Functions/FunctionHelpers.h>
 #include <Functions/IFunction.h>
 #include <Interpreters/Context.h>
-#include <Interpreters/Lemmatizers.cpp>
+#include <Interpreters/Lemmatizers.h>
 
 namespace DB
 {
@@ -62,7 +62,7 @@ private:
     Lemmatizers & lemmatizers;
 
 public:
-    FunctionLemmatize(Lemmatizers & lemmatizers_)
+    explicit FunctionLemmatize(Lemmatizers & lemmatizers_)
         : lemmatizers(lemmatizers_) {}
 
     String getName() const override { return name; }
diff --git a/src/Functions/synonyms.cpp b/src/Functions/synonyms.cpp
index 6c630861f60..b846a2e0486 100644
--- a/src/Functions/synonyms.cpp
+++ b/src/Functions/synonyms.cpp
@@ -33,7 +33,7 @@ private:
     SynonymsExtensions & extensions;
 
 public:
-    FunctionSynonyms(SynonymsExtensions & extensions_)
+    explicit FunctionSynonyms(SynonymsExtensions & extensions_)
         : extensions(extensions_) {}
 
     String getName() const override { return name; }
@@ -92,7 +92,7 @@ public:
         {
             std::string_view word(reinterpret_cast<const char *>(data.data() + offsets[i - 1]), offsets[i] - offsets[i - 1] - 1);
 
-            auto synset = extension->getSynonyms(word);
+            const auto * synset = extension->getSynonyms(word);
 
             if (synset)
             {
diff --git a/src/Interpreters/Lemmatizers.cpp b/src/Interpreters/Lemmatizers.cpp
index b2e63851d33..3e43d0aa090 100644
--- a/src/Interpreters/Lemmatizers.cpp
+++ b/src/Interpreters/Lemmatizers.cpp
@@ -15,17 +15,15 @@ namespace ErrorCodes
 }
 
 
-class Lemmatizer
+class Lemmatizer : public ILemmatizer
 {
 private:
     RdrLemmatizer lemmatizer;
 
 public:
-    using TokenPtr = std::shared_ptr<char []>;
+    explicit Lemmatizer(const String & path) : lemmatizer(path.data()) {}
 
-    Lemmatizer(const String & path) : lemmatizer(path.data()) {}
-
-    TokenPtr lemmatize(const char * token)
+    TokenPtr lemmatize(const char * token) override
     {
         return TokenPtr(lemmatizer.Lemmatize(token));
     }
diff --git a/src/Interpreters/Lemmatizers.h b/src/Interpreters/Lemmatizers.h
index b58839f05b2..dd3050aed45 100644
--- a/src/Interpreters/Lemmatizers.h
+++ b/src/Interpreters/Lemmatizers.h
@@ -9,12 +9,21 @@
 namespace DB
 {
 
-class Lemmatizer;
+class ILemmatizer
+{
+public:
+    using TokenPtr = std::shared_ptr<char []>;
+
+    virtual TokenPtr lemmatize(const char * token) = 0;
+
+    virtual ~ILemmatizer() = default;
+};
+
 
 class Lemmatizers
 {
 public:
-    using LemmPtr = std::shared_ptr<Lemmatizer>;
+    using LemmPtr = std::shared_ptr<ILemmatizer>;
 
 private:
     std::mutex mutex;
@@ -22,7 +31,7 @@ private:
     std::unordered_map<String, String> paths;
 
 public:
-    Lemmatizers(const Poco::Util::AbstractConfiguration & config);
+    explicit Lemmatizers(const Poco::Util::AbstractConfiguration & config);
 
     LemmPtr getLemmatizer(const String & name);
 };
diff --git a/src/Interpreters/SynonymsExtensions.cpp b/src/Interpreters/SynonymsExtensions.cpp
index 9671b605ed1..b2698e8f652 100644
--- a/src/Interpreters/SynonymsExtensions.cpp
+++ b/src/Interpreters/SynonymsExtensions.cpp
@@ -27,7 +27,7 @@ private:
     LookupTable table;
 
 public:
-    PlainSynonymsExtension(const String & path)
+    explicit PlainSynonymsExtension(const String & path)
     {
         std::ifstream file(path);
         if (!file.is_open())
@@ -66,7 +66,7 @@ private:
     wnb::wordnet wn;
 
 public:
-    WordnetSynonymsExtension(const String & path) : wn(path) {}
+    explicit WordnetSynonymsExtension(const String & path) : wn(path) {}
 
     const Synset * getSynonyms(const std::string_view & token) const override
     {
diff --git a/src/Interpreters/SynonymsExtensions.h b/src/Interpreters/SynonymsExtensions.h
index c8da2e338ac..3b00122a419 100644
--- a/src/Interpreters/SynonymsExtensions.h
+++ b/src/Interpreters/SynonymsExtensions.h
@@ -27,7 +27,7 @@ class SynonymsExtensions
 public:
     using ExtPtr = std::shared_ptr<ISynonymsExtension>;
 
-    SynonymsExtensions(const Poco::Util::AbstractConfiguration & config);
+    explicit SynonymsExtensions(const Poco::Util::AbstractConfiguration & config);
 
     ExtPtr getExtension(const String & name);