Decades since I saw this word, until I found it again in Elizabeth Gaskell’s Wives and Daughters. The dictionary says it refers to attractive articles of little value or use, or to practices or beliefs that are superficially or visually appealing but have little real value or worth. Showy but worthless: trumpery jewellery. Delusive or shallow: trumpery hope that lets us delude ourselves. Its origins lie with the French tromperie.
‘…an engagement which the two had made for a long walk together was cut very short by a very trumpery excuse.’
Source: Elizabeth Gaskell, Wives and Daughters, p.558