As a tester point of view, a good requirement is defined as 
a requirement which can be tested easily by creating test 
cases or by writting test scripts

Good requirement : As per the testers point of view , the 
requirement should not be complex .its should be clearly 
understood  and it should be one to one or one to many 
testing approaches  required to cover the requirement ,not 
many to many . It should be clearly ensure that it should 
not escalate any defect in future for the application. It 
should be so clear that all flexibility of the requirement 
can be easily find out and theses things can be take care 
during the  preparation and execution of the test cases of 
the application  .

a good requirement is easily understandable and testble

Good Requirements are those which are clear not only to the 
Programmer but also to the Tester.May be it is in a written 
form or in the Graphical form, because good requirements 
always make program Bug Free.

Necessary: meaning there is a need for it. There should be
no requirements just because it is nice to have one because
it will add up to the cost if the product. If the product
can meet real needs without it, then it isn’t necessary.
Cost Efficient: a cheaper cost with good quality is better.
Unambiguous: if the requirement can be interpreted in more
than one way, then it should be clarified. Ambiguous
requirements can lead to misunderstandings and unnecessary
effort.
Concise: meaning it should be simple and clear.

-there are no program that is bug free.

Clear,
Complete
Visible
Consistent
Measurable
Traceable
Resonable