have mercy

have mercy (third-person singular simple present has mercy, present participle having mercy, simple past and past participle had mercy)

1. (usually in the imperative) To show mercy or compassion; to stop inflicting punishment or a barrage.
   • 1844, Charles Dickens, The Chimes:

     "I have learnt it!" cried the old man. "Oh, have mercy on me in this hour, if, in my love for her, so young and good, I slandered Nature in the breasts of mothers rendered desperate! Pity my presumption, wickedness, and ignorance, and save her!"

• (to show mercy): spare