Word not found in any official scrabble dictionaries.
"Yadda" Definition
noun
One of a set of items which do not need to be specified; often used in conjunction with the catch phrase yadda yadda yadda.
Source: Wiktionary
interjection
Used three times in a row, or in combination with other words, to indicate part of a sentence which would be annoying to include, or which is incomprehensible, or which is just unimportant.
Source: Wiktionary