According to the Merriam-Webster dictionary, the word sympathy was first introduced to the English language in 1579.
“Sympathy”, mainly means “to show feelings of pity and sorrow for someone else’s misfortune“. A form of compassion.
The word “sympathy” roots in the ancient Greek word “συμπάθεια”, read “simpathia”. The Greek word itself is a compound word made up by the preposition “συν”, meaning “plus” and the word “πάθος”, meaning emotion.
The word “πάθος” itself has been brought into the English language as is. “Pathos“, used in the English language for the first time in 1591, means “the element that evokes pity or compassion”.
In its original meaning, “πάθος” describes “the strong emotion that reigns over logic and overwhelms an individual“.
However, the word “πάθος” itself derives from the verb “πάσχω”, read “pascho”, which means “to suffer”.
It stands to reason then that the word “sympathy” does not confine itself in representing the condition of a person showing compassion to another person. In its original meaning, “sympathy” describes the condition of a person sharing someone else’s emotions as if they were his or her own; sharing the suffering brought by the same emotions.
The antonym (another excellent example, or paradigm, of Greek rooted words) to “sympathy” is “antipathy“.