The spelling of the phrase "was mercy of" may seem confusing at first glance, but it can be broken down phonetically using IPA transcription. "Was" is pronounced /wɒz/, while "mercy" is pronounced /ˈmɜːsi/. "Of" is pronounced /əv/ after a vowel and /əf/ after a consonant. So, the full phrase can be transcribed as /wɒz ˈmɜːsi əv/. While the spelling may not be intuitive for non-native speakers, understanding the phonetics can aid in pronunciation.
There is no specific dictionary definition for the phrase "was mercy of," as it is likely a grammatically incorrect or incomplete phrase. However, it seems that you might be referring to the phrase "at the mercy of," which is an idiom used in English. Therefore, the following definition is provided for the phrase "at the mercy of":
"At the mercy of" is an idiomatic expression used to describe a situation where someone or something is completely under the control or power of another person, circumstance, or external force, with no ability to defend or protect oneself. It implies a lack of freedom, autonomy, or control in a given situation. The phrase often conveys a sense of vulnerability and helplessness, suggesting that the person or thing subjected to it is entirely dependent on the whims or decisions of others. It can be used to describe individuals or entities facing adverse conditions, threats, or unfavorable circumstances over which they have no influence or say. For instance, someone caught in a severe storm may be described as being "at the mercy of the elements," indicating their powerlessness against the forces of nature. Alternatively, a person in an unequal power dynamic or disadvantaged position in a relationship might be said to be "at the mercy of their employer" or "at the mercy of circumstances."