diff --git a/src/stardict_lib.cpp b/src/stardict_lib.cpp
index bedf987..4202538 100644
--- a/src/stardict_lib.cpp
+++ b/src/stardict_lib.cpp
@@ -1037,133 +1037,6 @@ void Libs::load(const std::list<std::string> &dicts_dirs,
                   });
 }
 
-const gchar *Libs::poGetCurrentWord(glong *iCurrent)
-{
-    const gchar *poCurrentWord = nullptr;
-    const gchar *word;
-    for (std::vector<Dict *>::size_type iLib = 0; iLib < oLib.size(); iLib++) {
-        if (iCurrent[iLib] == INVALID_INDEX)
-            continue;
-        if (iCurrent[iLib] >= narticles(iLib) || iCurrent[iLib] < 0)
-            continue;
-        if (poCurrentWord == nullptr) {
-            poCurrentWord = poGetWord(iCurrent[iLib], iLib);
-        } else {
-            word = poGetWord(iCurrent[iLib], iLib);
-
-            if (stardict_strcmp(poCurrentWord, word) > 0)
-                poCurrentWord = word;
-        }
-    }
-    return poCurrentWord;
-}
-
-const gchar *Libs::poGetNextWord(const gchar *sWord, glong *iCurrent)
-{
-    // the input can be:
-    // (word,iCurrent),read word,write iNext to iCurrent,and return next word. used by TopWin::NextCallback();
-    // (nullptr,iCurrent),read iCurrent,write iNext to iCurrent,and return next word. used by AppCore::ListWords();
-    const gchar *poCurrentWord = nullptr;
-    size_t iCurrentLib = 0;
-    const gchar *word;
-
-    glong nextWordIdx = 0;
-    std::set<glong> wordIndices;
-
-    for (size_t iLib = 0; iLib < oLib.size(); ++iLib) {
-        wordIndices.clear();
-        if (sWord) {
-            if (oLib[iLib]->Lookup(sWord, wordIndices, nextWordIdx)) {
-                // In order to progress over words which have multiple entries,
-                // pick the smallest index larger than iCurrent.
-                for (auto &wordIdx : wordIndices) {
-                    if (wordIdx > iCurrent[iLib]) {
-                        iCurrent[iLib] = wordIdx;
-                        break;
-                    }
-                }
-            } else {
-                iCurrent[iLib] = nextWordIdx;
-            }
-        }
-        if (iCurrent[iLib] == INVALID_INDEX)
-            continue;
-        if (iCurrent[iLib] >= narticles(iLib) || iCurrent[iLib] < 0)
-            continue;
-        if (poCurrentWord == nullptr) {
-            poCurrentWord = poGetWord(iCurrent[iLib], iLib);
-            iCurrentLib = iLib;
-        } else {
-            word = poGetWord(iCurrent[iLib], iLib);
-
-            if (stardict_strcmp(poCurrentWord, word) > 0) {
-                poCurrentWord = word;
-                iCurrentLib = iLib;
-            }
-        }
-    }
-    if (poCurrentWord) {
-        iCurrent[iCurrentLib]++;
-        for (std::vector<Dict *>::size_type iLib = 0; iLib < oLib.size(); iLib++) {
-            if (iLib == iCurrentLib)
-                continue;
-            if (iCurrent[iLib] == INVALID_INDEX)
-                continue;
-            if (iCurrent[iLib] >= narticles(iLib) || iCurrent[iLib] < 0)
-                continue;
-            if (strcmp(poCurrentWord, poGetWord(iCurrent[iLib], iLib)) == 0)
-                iCurrent[iLib]++;
-        }
-        poCurrentWord = poGetCurrentWord(iCurrent);
-    }
-    return poCurrentWord;
-}
-
-const gchar *
-Libs::poGetPreWord(glong *iCurrent)
-{
-    // used by TopWin::PreviousCallback(); the iCurrent is cached by AppCore::TopWinWordChange();
-    const gchar *poCurrentWord = nullptr;
-    std::vector<Dict *>::size_type iCurrentLib = 0;
-    const gchar *word;
-
-    for (std::vector<Dict *>::size_type iLib = 0; iLib < oLib.size(); iLib++) {
-        if (iCurrent[iLib] == INVALID_INDEX)
-            iCurrent[iLib] = narticles(iLib);
-        else {
-            if (iCurrent[iLib] > narticles(iLib) || iCurrent[iLib] <= 0)
-                continue;
-        }
-        if (poCurrentWord == nullptr) {
-            poCurrentWord = poGetWord(iCurrent[iLib] - 1, iLib);
-            iCurrentLib = iLib;
-        } else {
-            word = poGetWord(iCurrent[iLib] - 1, iLib);
-            if (stardict_strcmp(poCurrentWord, word) < 0) {
-                poCurrentWord = word;
-                iCurrentLib = iLib;
-            }
-        }
-    }
-
-    if (poCurrentWord) {
-        iCurrent[iCurrentLib]--;
-        for (std::vector<Dict *>::size_type iLib = 0; iLib < oLib.size(); iLib++) {
-            if (iLib == iCurrentLib)
-                continue;
-            if (iCurrent[iLib] > narticles(iLib) || iCurrent[iLib] <= 0)
-                continue;
-            if (strcmp(poCurrentWord, poGetWord(iCurrent[iLib] - 1, iLib)) == 0) {
-                iCurrent[iLib]--;
-            } else {
-                if (iCurrent[iLib] == narticles(iLib))
-                    iCurrent[iLib] = INVALID_INDEX;
-            }
-        }
-    }
-    return poCurrentWord;
-}
-
 bool Libs::LookupSimilarWord(const gchar *sWord, std::set<glong> &iWordIndices, int iLib)
 {
     bool bFound = false;
diff --git a/src/stardict_lib.hpp b/src/stardict_lib.hpp
index f864604..4161c4f 100644
--- a/src/stardict_lib.hpp
+++ b/src/stardict_lib.hpp
@@ -195,9 +195,6 @@ public:
             return nullptr;
         return oLib[iLib]->get_data(iIndex);
     }
-    const gchar *poGetCurrentWord(glong *iCurrent);
-    const gchar *poGetNextWord(const gchar *word, glong *iCurrent);
-    const gchar *poGetPreWord(glong *iCurrent);
     bool LookupWord(const gchar *sWord, std::set<glong> &iWordIndices, int iLib)
     {
         return oLib[iLib]->Lookup(sWord, iWordIndices);