weaken
/ˈwiːkən ˈव़ीकन्/ verb [I, T] 1 to become less strong; to make somebody/something less strong कमज़ोर हो जाना; (व्यकि्त या वस्तु को) कमज़ोर कर देना
The building had been weakened by the earthquake.
✪ विलोम strengthen