1 at the mercy of | Definition of at the mercy of

mercy

noun
mer·​cy | \ ˈmÉ™r-sÄ“ How to pronounce mercy (audio) \
plural mercies

Definition of mercy

1a : compassion or forbearance (see forbearance sense 1) shown especially to an offender or to one subject to one's power also : lenient or compassionate treatment begged for mercy
b : imprisonment rather than death imposed as penalty for first-degree murder
2a : a blessing that is an act of divine favor or compassion May God have mercy on us.
b : a fortunate circumstance it was a mercy they found her before she froze
3 : compassionate treatment of those in distress works of mercy among the poor
at the mercy of
: wholly in the power of : with no way to protect oneself against