Simplified version of your look_w function

look_w.py

@@ -0,0 +1,16 @@
+# Open words.txt.  Assumes words.txt is in same folder as look_w.py
+words = open('words.txt').read().split()
+
+
+def look_w(word, num):
+    # Looking words that in the words list
+    # by number of letters and alphabets
+    return [w for w in words if len(w) == num and
+            all(w.lower().count(c) <= word.lower().count(c) for c in w.lower())]
+
+
+# Usage
+print(look_w('insane', 6))  # prints ['inanes', 'insane', 'sienna']
+print(look_w('quit', 3))    # prints ['ITU', 'qui', 'Tiu', 'tui', 'UIT', 'uti']
+print(look_w('quit', 4))    # prints ['quit']
+print(look_w('cake', 99))   # prints []

read_english_dictionary.py

@@ -1,16 +1,11 @@
-import json
-import os, sys
-
 def load_words():
-    try:
-        filename = os.path.dirname(sys.argv[0])+"\\"+"words_dictionary.json"
-        with open(filename,"r") as english_dictionary:
-            valid_words = json.load(english_dictionary)
-            return valid_words
-    except Exception as e:
-        return str(e)
+    with open('words_alpha.txt') as word_file:
+        valid_words = set(word_file.read().split())
+
+    return valid_words
+
 
 if __name__ == '__main__':
     english_words = load_words()
     # demo print
-    print(english_words["fate"])
+    print('fate' in english_words)