diff --git a/src/query/query_parser.cpp b/src/query/query_parser.cpp
index 7ecb7048..02bc5106 100644
--- a/src/query/query_parser.cpp
+++ b/src/query/query_parser.cpp
@@ -1,5 +1,7 @@
-#include "query/query_parser.hpp"
+#include <spdlog/spdlog.h>
+
 #include "query/queries.hpp"
+#include "query/query_parser.hpp"
 
 namespace pisa {
 
@@ -13,6 +15,8 @@ auto QueryParser::parse(std::string_view query) -> Query {
     for (auto token: *tokens) {
         if (auto id = (*m_term_map)(token); id) {
             query_ids.push_back(*id);
+        } else {
+            spdlog::warn("Term `{}` not found and will be ignored", token);
         }
     }
     return {std::move(id), std::move(query_ids), {}};
diff --git a/src/token_filter.cpp b/src/token_filter.cpp
index 278d286a..25e9d0ac 100644
--- a/src/token_filter.cpp
+++ b/src/token_filter.cpp
@@ -1,8 +1,7 @@
-#include "pisa/token_filter.hpp"
-
-#include <cctype>
-
 #include <boost/algorithm/string.hpp>
+#include <spdlog/spdlog.h>
+
+#include "pisa/token_filter.hpp"
 
 namespace pisa {
 
@@ -60,6 +59,7 @@ auto StopWordRemover::filter(std::string_view input) const -> std::unique_ptr<To
 
 auto StopWordRemover::filter(std::string input) const -> std::unique_ptr<TokenStream> {
     if (m_stopwords.find(input) != m_stopwords.end()) {
+        spdlog::warn("Term `{}` is a stopword and will be ignored", input);
         return std::make_unique<EmptyTokenStream>();
     }
     return std::make_unique<SingleTokenStream>(std::move(input));