diff --git a/lib/dry/inflector.rb b/lib/dry/inflector.rb
index b09d23a..73398f4 100644
--- a/lib/dry/inflector.rb
+++ b/lib/dry/inflector.rb
@@ -298,7 +298,9 @@ def underscore(input)
     # @since 0.1.0
     # @api private
     def uncountable?(input)
-      input.match?(/\A[[:space:]]*\z/) || inflections.uncountables.include?(input.downcase)
+      input.match?(/\A[[:space:]]*\z/) ||
+        inflections.uncountables.include?(input.downcase) ||
+        inflections.uncountables.include?(input.split(/_|\b/).last.downcase)
     end
 
     # @return [String]
diff --git a/lib/dry/inflector/inflections/defaults.rb b/lib/dry/inflector/inflections/defaults.rb
index 83bd5ed..3ea6ca0 100644
--- a/lib/dry/inflector/inflections/defaults.rb
+++ b/lib/dry/inflector/inflections/defaults.rb
@@ -56,7 +56,7 @@ def self.singular(inflect)
           inflect.singular(/s\z/i, "")
           inflect.singular(/(n)ews\z/i, '\1ews')
           inflect.singular(/([ti])a\z/i, '\1um')
-          inflect.singular(/((a)naly|(b)a|(d)iagno|(p)arenthe|(p)rogno|(s)ynop|(t)he)(sis|ses)\z/i,
+          inflect.singular(/(analy|(b)a|(d)iagno|(p)arenthe|(p)rogno|(s)ynop|(t)he)(sis|ses)\z/i,
                            '\1\2sis')
           inflect.singular(/(^analy)(sis|ses)\z/i, '\1sis')
           inflect.singular(/([^f])ves\z/i, '\1fe')
@@ -75,7 +75,7 @@ def self.singular(inflect)
           inflect.singular(/(cris|ax|test)(is|es)\z/i, '\1is')
           inflect.singular(/(octop|vir)(us|i)\z/i, '\1us')
           inflect.singular(/(alias|status)(es)?\z/i, '\1')
-          inflect.singular(/^(ox)en/i, '\1')
+          inflect.singular(/(ox)en/i, '\1')
           inflect.singular(/(vert|ind)ices\z/i, '\1ex')
           inflect.singular(/(matr)ices\z/i, '\1ix')
           inflect.singular(/(quiz)zes\z/i, '\1')
diff --git a/spec/unit/dry/inflector/singularize_spec.rb b/spec/unit/dry/inflector/singularize_spec.rb
index 39fe771..a33c9dc 100644
--- a/spec/unit/dry/inflector/singularize_spec.rb
+++ b/spec/unit/dry/inflector/singularize_spec.rb
@@ -6,6 +6,18 @@
       it "singularizes #{plural} => #{singular}" do
         expect(subject.singularize(i(plural))).to eq(singular)
       end
+
+      it "singularizes test_#{plural} => test_#{singular}" do
+        expect(subject.singularize(i("test_#{plural}"))).to eq("test_#{singular}")
+      end
+
+      it "singularizes test-#{plural} => test-#{singular}" do
+        expect(subject.singularize(i("test-#{plural}"))).to eq("test-#{singular}")
+      end
+
+      it "singularizes 'test #{plural}' => 'test #{singular}'" do
+        expect(subject.singularize(i("test #{plural}"))).to eq("test #{singular}")
+      end
     end
 
     Fixtures::Singularize.pending.each do |plural, singular|