at the mercy of

Related to at the mercy of: without a hitch, take a back seat, along the lines

at the mercy of (someone or something)

Subject to the control or actions of a particular person or thing. When you're a minor, you're totally at the mercy of your parents. When you travel by public transportation, you're always at the mercy of the weather. Her fate is at the mercy of the jury—it's their decision now.
See also: mercy, of
Farlex Dictionary of Idioms.

at the mercy of someone

 and at someone's mercy
Fig. under the control of someone; without defense against someone. We were left at the mercy of the arresting officer. Mrs. Franklin wanted Mr. Franklin at her mercy.
See also: mercy, of
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

at the mercy of

1. Also, at someone's mercy. Subject to the power of, helpless against, as in The captured rebels were at the mercy of the army commander. [Late 1500s]
2. Without any protection against, as in On top of Mount Washington we were at the mercy of the elements. [Late 1600s]
See also: mercy, of
The American Heritage® Dictionary of Idioms by Christine Ammer.

(be) at the mercy of somebody/something

not be able to stop somebody/something harming you because they have power or control over you: Small businesses are completely at the mercy of the banks these days. The little ship was at the mercy of the storm.
See also: mercy, of, somebody, something
Farlex Partner Idioms Dictionary

at the mercy of

Without any protection against; helpless before: drifting in an open boat, at the mercy of the elements.
See also: mercy, of
American Heritage® Dictionary of the English Language, Fifth Edition.
See also:
  • at the mercy of (someone or something)
  • at (someone's or something's) mercy
  • be at the mercy of (something)
  • So what if I do?
  • stand on (one's)/its own
  • Mr Right
  • be on a hiding to nothing
  • Miss Right
  • missus
  • ms