Functional Testing : 
The portion of security testing in which the advertised 
features of a system are tested for correct operation.
              OR
Quality assurance that a web site performs properly. All 
aspects of the user interface, navigation between pages and 
off-site, multilingual navigation, etc. are tested. Testing 
is required in all the current browsers and on the major 
operating systems and platforms.

functional testing is nothing but whether the given 
function is working or not as per the specifications
Ex: field validation, Navigation e.t.c

Functionality Testing is nothing but to check whether our 
application is equal to customer requirements or not\|

Here we will do lot more tests
Ex: Intersystem Testing
     Error Handling testing

functionality testing comes under functional testing only 
i.e mannual testing

functional testing is nothing but whether the given 
function is working or not as per the specifications
Ex: field validation, Navigation e.t.c

Functionality Testing is nothing but to check whether our 
application is equal to customer requirements or not\|

Here we will do lot more tests
Ex: Intersystem Testing
     Error Handling testing

Hi,
This is shijath ali, an upcoming tester........

Functional Testing: This is nothing but Black box testing 
i.e. testing carried out to justify the behaviour of the 
application as per the requirements and not inclined 
towards structural part.

Functionality Testing: This is also a part of black box 
type of testing carried out inorder to aver the validation 
or functionality of a field as per the requirements.

Plz correct me if iam wrong........

functional testing is sub-set of functionality testing. 

Functional Testing specific to module but functionality
testing is related with whole application.

testing the basic funationality of an application is called 
functional tesing