The word "衷心" (zhōngxīn), meaning "wholehearted" or "sincere", is formed through a classic Chinese lexical process where two synonymous or closely related characters combine to create a single, reinforced meaning. The character "衷" (zhōng) originally referred to one's inner feelings or true heart, derived from the concept of clothing ("衣") enveloping the center ("中"), metaphorically suggesting what is held within. It is paired with "心" (xīn), the direct and fundamental character for "heart" or "mind". Together, "衷" and "心" form a binome (a two-character compound) where both components semantically reinforce the same core idea of innermost, genuine sentiment, resulting in a term that powerfully conveys heartfelt sincerity and deep conviction.