Relating to, involving, or of the nature of synthesis. Chemistry Produced by synthesis, especially not of natural origin. Not natural or genuine; artificial or contrived: "counterfeit rhetoric that flourishes when passions are synthetic\u201d ( George F. Will). Prepared or made artificially: synthetic leather. See Synonyms at artificial. Linguistics Relating to or being a language, such as Latin or Russian, that uses inflectional affixes to express syntactic relationships. Logic & Philosophy Relating to or being a proposition that attributes to a subject a predicate not inherent in the subject and that does not result in a contradiction if negated. A synthetic chemical compound or material.