diff --git a/src/interfaces/node.cpp b/src/interfaces/node.cpp
--- a/src/interfaces/node.cpp
+++ b/src/interfaces/node.cpp
@@ -51,7 +51,7 @@
         ChainstateManager &chainman() { return *Assert(m_context->chainman); }
 
     public:
-        NodeImpl(NodeContext *context) { setContext(context); }
+        explicit NodeImpl(NodeContext *context) { setContext(context); }
         void initLogging() override { InitLogging(*Assert(m_context->args)); }
         void initParameterInteraction() override {
             InitParameterInteraction(*Assert(m_context->args));
diff --git a/src/invrequest.cpp b/src/invrequest.cpp
--- a/src/invrequest.cpp
+++ b/src/invrequest.cpp
@@ -202,7 +202,7 @@
     const PriorityComputer &m_computer;
 
 public:
-    ByInvIdViewExtractor(const PriorityComputer &computer)
+    explicit ByInvIdViewExtractor(const PriorityComputer &computer)
         : m_computer(computer) {}
     using result_type = ByInvIdView;
     result_type operator()(const Announcement &ann) const {
@@ -587,7 +587,7 @@
                       EmplaceExpiredFun emplaceExpired) {
         clearExpired();
         // Iterate over all CANDIDATE_DELAYED and REQUESTED from old to new, as
-        // long as they're in the past, and convert them to CANDIDATE_READY and
+        // long as they're in the past, and convert them to CANDIDATE_READY andc
         // COMPLETED respectively.
         while (!m_index.empty()) {
             auto it = m_index.get<ByTime>().begin();
@@ -620,7 +620,7 @@
     }
 
 public:
-    InvRequestTrackerImpl(bool deterministic)
+    explicit InvRequestTrackerImpl(bool deterministic)
         : m_computer(deterministic),
           // Explicitly initialize m_index as we need to pass a reference to
           // m_computer to ByInvIdViewExtractor.
diff --git a/src/rpc/request.h b/src/rpc/request.h
--- a/src/rpc/request.h
+++ b/src/rpc/request.h
@@ -41,7 +41,7 @@
     std::string peerAddr;
     const util::Ref &context;
 
-    JSONRPCRequest(const util::Ref &contextIn)
+    explicit JSONRPCRequest(const util::Ref &contextIn)
         : id(NullUniValue), params(NullUniValue), context(contextIn) {}
 
     //! Initializes request information from another request object and the
diff --git a/src/script/descriptor.cpp b/src/script/descriptor.cpp
--- a/src/script/descriptor.cpp
+++ b/src/script/descriptor.cpp
@@ -187,7 +187,7 @@
     uint32_t m_expr_index;
 
 public:
-    PubkeyProvider(uint32_t exp_index) : m_expr_index(exp_index) {}
+    explicit PubkeyProvider(uint32_t exp_index) : m_expr_index(exp_index) {}
 
     virtual ~PubkeyProvider() = default;
 
diff --git a/src/test/fuzz/signature_checker.cpp b/src/test/fuzz/signature_checker.cpp
--- a/src/test/fuzz/signature_checker.cpp
+++ b/src/test/fuzz/signature_checker.cpp
@@ -22,7 +22,7 @@
     FuzzedDataProvider &m_fuzzed_data_provider;
 
 public:
-    FuzzedSignatureChecker(FuzzedDataProvider &fuzzed_data_provider)
+    explicit FuzzedSignatureChecker(FuzzedDataProvider &fuzzed_data_provider)
         : m_fuzzed_data_provider(fuzzed_data_provider) {}
 
     bool CheckSig(const std::vector<uint8_t> &scriptSig,
diff --git a/src/tinyformat.h b/src/tinyformat.h
--- a/src/tinyformat.h
+++ b/src/tinyformat.h
@@ -575,7 +575,7 @@
         FormatArg() : m_value(NULL), m_formatImpl(NULL), m_toIntImpl(NULL) {}
 
         template <typename T>
-        FormatArg(const T &value)
+        explicit FormatArg(const T &value)
             : m_value(static_cast<const void *>(&value)),
               m_formatImpl(&formatImpl<T>), m_toIntImpl(&toIntImpl<T>) {}
 
@@ -1022,7 +1022,7 @@
     public:
 #ifdef TINYFORMAT_USE_VARIADIC_TEMPLATES
         template <typename... Args>
-        FormatListN(const Args &...args)
+        explicit FormatListN(const Args &...args)
             : FormatList(&m_formatterStore[0], N), m_formatterStore{
                                                        FormatArg(args)...} {
             static_assert(sizeof...(args) == N, "Number of args must be N");
diff --git a/src/util/hash_type.h b/src/util/hash_type.h
--- a/src/util/hash_type.h
+++ b/src/util/hash_type.h
@@ -11,7 +11,7 @@
 
 public:
     BaseHash() : m_hash() {}
-    BaseHash(const HashType &in) : m_hash(in) {}
+    explicit BaseHash(const HashType &in) : m_hash(in) {}
 
     uint8_t *begin() { return m_hash.begin(); }
 
diff --git a/src/wallet/bdb.h b/src/wallet/bdb.h
--- a/src/wallet/bdb.h
+++ b/src/wallet/bdb.h
@@ -49,7 +49,7 @@
     std::unordered_map<std::string, WalletDatabaseFileId> m_fileids;
     std::condition_variable_any m_db_in_use;
 
-    BerkeleyEnvironment(const fs::path &env_directory);
+    explicit BerkeleyEnvironment(const fs::path &env_directory);
     BerkeleyEnvironment();
     ~BerkeleyEnvironment();
     void Reset();
diff --git a/src/wallet/scriptpubkeyman.h b/src/wallet/scriptpubkeyman.h
--- a/src/wallet/scriptpubkeyman.h
+++ b/src/wallet/scriptpubkeyman.h
@@ -176,7 +176,7 @@
     WalletStorage &m_storage;
 
 public:
-    ScriptPubKeyMan(WalletStorage &storage) : m_storage(storage) {}
+    explicit ScriptPubKeyMan(WalletStorage &storage) : m_storage(storage) {}
     virtual ~ScriptPubKeyMan(){};
     virtual bool GetNewDestination(const OutputType type, CTxDestination &dest,
                                    std::string &error) {
@@ -633,7 +633,7 @@
     const LegacyScriptPubKeyMan &m_spk_man;
 
 public:
-    LegacySigningProvider(const LegacyScriptPubKeyMan &spk_man)
+    explicit LegacySigningProvider(const LegacyScriptPubKeyMan &spk_man)
         : m_spk_man(spk_man) {}
 
     bool GetCScript(const CScriptID &scriptid, CScript &script) const override {