diff --git a/findspam.py b/findspam.py
index e56daaa240..a7b4096fb2 100644
--- a/findspam.py
+++ b/findspam.py
@@ -561,40 +561,51 @@ def mevaqesh_troll(s, *args):
         return False, ""
 
 
-def blacklist_factory(wb=[], nwb=[], **kwargs):
-    pattern = r'(?is){}'.format("|".join(chain(
-        (r"(?P<wb{}>\b{}\b)".format(i, keyword) for i, keyword in enumerate(wb)),
-        (r"(?P<nwb{}>{})".format(i, keyword) for i, keyword in enumerate(nwb))
-    )))
+class BlacklistFactory:
+    def __init__(self, wb=[], nwb=[], **kwargs):
+        self.patterns = {}
+        self.info = regex._Info(0, chr, kwargs)
+        parts = []
 
-    compiled_pattern = regex.compile(pattern, **kwargs)
-    del pattern
+        for i, keyword in enumerate(wb):
+            self.add_pattern(parts, keyword, i, wb=True)
 
-    def f(s, *args):
+        for i, keyword in enumerate(nwb):
+            self.add_pattern(parts, keyword, i, wb=False)
+
+        self.compiled_regex = regex.compile("(?is)" + "|".join(parts), **kwargs)
+
+    def add_pattern(self, parts, pattern, line, wb=False):
+        wb_description = "wb" if wb else "nwb"
+        self.patterns[self.info.group_count + len(self.patterns)] = (pattern, line, wb_description)
+
+        while True:
+            try:
+                regex._regex_core._parse_pattern(regex._Source(pattern), self.info)
+            except regex._regex_core._UnscopedFlagSet:
+                continue
+            break
+
+        if wb:
+            parts.append("(\\b{}\\b)".format(pattern))
+        else:
+            parts.append("({})".format(pattern))
+
+    def __call__(self, s, *args):
         why = []
 
-        for match in compiled_pattern.finditer(s):
-            group = match.lastgroup
+        for match in self.compiled_regex.finditer(s):
+            pattern, line, wb = self.patterns[match.lastindex - 1]
             start, end = match.span()
 
-            if group[:3] == "nwb":
-                i = int(group[3:])
-                why.append("Position {}-{}: {} (nwb pattern `{}` on L{})"
-                           .format(start, end, match.group(), nwb[i], i + 1))
-            elif group[:2] == "wb":
-                i = int(group[2:])
-                why.append("Position {}-{}: {} (wb pattern `{}` on L{})"
-                           .format(start, end, match.group(), wb[i], i + 1))
-            else:
-                why.append("Position {}-{}: {} (can't retrieve matching pattern)".format(start, end, match.group()))
+            why.append("Position {}-{}: {} ({} pattern `{}` on L{})"
+                       .format(start + 1, end + 1, match.group(), wb, pattern, line + 1))
 
         if len(why) > 0:
             return True, ", ".join(why)
         else:
             return False, ""
 
-    return f
-
 
 load_blacklists()
 
@@ -732,11 +743,11 @@ class FindSpam:
         #
         # Category: Bad keywords
         # The big list of bad keywords, for titles and posts
-        {'method': blacklist_factory(wb=GlobalVars.bad_keywords, nwb=bad_keywords_nwb, city=city_list),
+        {'method': BlacklistFactory(wb=GlobalVars.bad_keywords, nwb=bad_keywords_nwb, city=city_list),
          'all': True, 'sites': [], 'reason': "bad keyword in {}", 'title': True, 'body': True, 'username': True,
          'stripcodeblocks': False, 'body_summary': True, 'max_rep': 4, 'max_score': 1},
         # The small list of *potentially* bad keywords, for titles and posts
-        {'method': blacklist_factory(wb=list(GlobalVars.watched_keywords)),
+        {'method': BlacklistFactory(wb=list(GlobalVars.watched_keywords)),
          'reason': 'potentially bad keyword in {}',
          'all': True, 'sites': [], 'title': True, 'body': True, 'username': True,
          'stripcodeblocks': False, 'body_summary': True, 'max_rep': 30, 'max_score': 1},
@@ -865,7 +876,7 @@ class FindSpam:
         #
         # Category: Suspicious links
         # Blacklisted sites
-        {'method': blacklist_factory(nwb=GlobalVars.blacklisted_websites), 'all': True,
+        {'method': BlacklistFactory(nwb=GlobalVars.blacklisted_websites), 'all': True,
          'sites': [], 'reason': "blacklisted website in {}", 'title': True, 'body': True, 'username': False,
          'stripcodeblocks': False, 'body_summary': True, 'max_rep': 50, 'max_score': 5},
         # Suspicious sites
@@ -1112,7 +1123,7 @@ class FindSpam:
         #
         # Category: other
         # Blacklisted usernames
-        {'method': blacklist_factory(nwb=GlobalVars.blacklisted_usernames), 'all': True, 'sites': [],
+        {'method': BlacklistFactory(nwb=GlobalVars.blacklisted_usernames), 'all': True, 'sites': [],
          'reason': "blacklisted username", 'title': False, 'body': False, 'username': True, 'stripcodeblocks': False,
          'body_summary': False, 'max_rep': 1, 'max_score': 0},
         {'regex': u"(?i)^jeff$", 'all': False, 'sites': ["parenting.stackexchange.com"],