diff --git a/doc/0.getting_started.md b/doc/0.getting_started.md
index 45139aa..3afab9d 100644
--- a/doc/0.getting_started.md
+++ b/doc/0.getting_started.md
@@ -195,6 +195,10 @@ under the `constraints` key. The available constraints are:
    be present in the posts descriptions. Typically, if you expect "parking" to
    be in all the posts Flatisfy fetches for you, you can set
    `description_should_contain: ["parking"]`.
+ * `description_should_not_contain` lets you specify a list of terms that should
+   never occur in the posts descriptions. Typically, if you wish to avoid
+   "coloc" in the posts Flatisfy fetches for you, you can set
+   `description_should_not_contain: ["coloc"]`.
 
 
 You can think of constraints as "a set of criterias to filter out flats". You
diff --git a/flatisfy/config.py b/flatisfy/config.py
index b1f6c34..f233ce3 100644
--- a/flatisfy/config.py
+++ b/flatisfy/config.py
@@ -38,6 +38,7 @@ DEFAULT_CONFIG = {
             "bedrooms": (None, None),  # (min, max)
             "minimum_nb_photos": None,  # min number of photos
             "description_should_contain": [],  # list of terms
+            "description_should_not_contain": [],  # list of terms
             "time_to": {}  # Dict mapping names to {"gps": [lat, lng],
                            #                        "time": (min, max),
                            #                        "mode": Valid mode }
@@ -177,6 +178,13 @@ def validate_config(config, check_with_data):
                 for term in constraint["description_should_contain"]:
                     assert isinstance(term, str)
 
+            assert "description_should_not_contain" in constraint
+            assert isinstance(constraint["description_should_not_contain"],
+                              list)
+            if constraint["description_should_not_contain"]:
+                for term in constraint["description_should_not_contain"]:
+                    assert isinstance(term, str)
+
             assert "house_types" in constraint
             assert constraint["house_types"]
             for house_type in constraint["house_types"]:
diff --git a/flatisfy/filters/__init__.py b/flatisfy/filters/__init__.py
index 2e9bf62..5b31075 100644
--- a/flatisfy/filters/__init__.py
+++ b/flatisfy/filters/__init__.py
@@ -117,16 +117,25 @@ def refine_with_details_criteria(flats_list, constraint):
             )
             is_ok[i] = False
 
-        has_terms_in_description = True
+        has_all_good_terms_in_description = True
         if constraint["description_should_contain"]:
-            has_terms_in_description = all(
+            has_all_good_terms_in_description = all(
                 term in flat['text']
                 for term in constraint["description_should_contain"]
             )
-        if not has_terms_in_description:
+
+        has_a_bad_term_in_description = False
+        if constraint["description_should_not_contain"]:
+            has_a_bad_term_in_description = any(
+                term in flat['text']
+                for term in constraint["description_should_not_contain"]
+            )
+
+        if (not has_all_good_terms_in_description
+            or has_a_bad_term_in_description):
             LOGGER.info(
                 ("Description for flat %s does not contain all the required "
-                 "terms."),
+                 "terms, or contains a blacklisted term."),
                 flat["id"]
             )
             is_ok[i] = False