1. to cause (a breed or strain) to become mixed or impure by crossing with other breeds; to make mongrel
Usage: chiefly British spelling; American English typically uses 'mongrelize'; often used in contexts of animal breeding or genetics
2. to degrade or corrupt (something) by mixing with inferior elements
Usage: figurative use; formal or literary

Examples

• The breeder warned that allowing uncontrolled mating would mongrelise the bloodline.
• Critics argued that the merger would mongrelise the company's original mission.
• Excessive cross-breeding mongrelised the once-pure strain of the dog.
• Some purists feared that foreign influences would mongrelise the traditional art form.
• The conservationists worked to prevent the native species from being mongrelised by introduced populations.
• He believed that commercial interests had mongrelised the integrity of the institution.