Costumed dream meaning is explained below using 1 different source. Each interpretation is shown with its source.
Interpretation 1 — Michael and Elizabeth Thiessen
If you are wearing a costume this could indicate that you are trying to hide your true self, or you inner feelings behind a facade of duplicity; you may not be wholly honest with a loved one and have a fear of being found out.
If you are wearing a ridiculous costume, such as a chicken suit, this could indicate that you are being foolish about certain matters in your life and must look to the other symbols to find out just what it is.
Source: Encyclopedia of Dreams • Author: Michael and Elizabeth Thiessen