We don't have synonyms for trans-fat yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are trans fat, transfat and transfan.
(n) :
Alternative form of trans fat. [(organic chemistry) An unsaturated fat with carbon-carbon double bonds in the trans configuration, especially one prepared by partial hydrogenation, associated with an elevated risk of coronary heart disease.]
(n) :
Alternative form of trans fat. [(organic chemistry) An unsaturated fat with carbon-carbon double bonds in the trans configuration, especially one prepared by partial hydrogenation, associated with an elevated risk of coronary heart disease.]