***** NOT A TEACHER *****
Hello, Randa:
I am replying because "tacky" ("in poor taste") is one of my favorite words. I certainly do NOT think that it is the same as "dowdy" or "scruffy."
For example, when I take my walks and pass some beautiful houses, I occasionally see a sign on the front lawn that says, "Please pick up after your dog." [Plain English: If your dog uses our lawn as a toilet, pick up the results and place them in a bag.]
To me, such a sign is really tacky. It lessens the dignity of a beautiful house and its lawn -- in my opinion.