watchdog
US
UK watchdog n: (guard dog)
SC 看门狗 kān mén gǒu
TC 看門狗
TC 看門狗
SC 看家狗 kān mén gǒu，kān jiā gǒu
The sign says there's a watchdog on the premises all night.
watchdog n: figurative (guardian, defender) (比喻)
SC 忠实的警卫，守护者 zhōng shí de jǐng wèi，shǒu hù zhě
The agency acts as a watchdog of the water industry.