The success of object-oriented approach in the software development can be mainly attributed to its effectiveness in controlling the complexity & maintainability, and in increasing the reusability of its classes. But one needs to measure the strength/weakness of the classes and their dependencies in order to control and reuse them. This paper proposes a new metric named as class weakness, which measures the weakness within the class and weakness due to dependency of the class over rest of the classes. The intra-class weakness is computed with help of usage of various data members in the corresponding member functions. The inter-class weakness is found with help of calculating the dependencies (direct as well as indirect) of the class over remaining classes in the object-oriented software.