Something tawdry is showy but cheap and of poor quality.
To find the source of this word we must travel to Ely, a city whose cathedral dominates the flat fen landscape of East Anglia. Long before the cathedral was built, a small religious house had been established there in the seventh century by Ethelreda, the daughter of King Anna of East Anglia. She died in 679. Sixty years later the Venerable Bede wrote that her death had been caused by a growth in her throat, which she had said was a punishment for wearing necklaces in her youth.
She eventually became the patron saint of Ely, under the Norman French name of St Audrey, and her feast day, 17 October, was celebrated by a fair. One of the favourite items sold was a band of fine silk lace or ribbon worn about the neck in memory of the city’s patron saint. This became known as St Audrey’s lace, but by the end of the sixteenth century it had been corrupted to tawdry lace.
Eventually the first word was taken to be a description; by the nature of goods sold at fairs they often looked good until the buyer got them home, so the word became attached to such cheap and showy items, and not just at Ely.