megillah (n.) Look up megillah at Dictionary.com
"long, tedious, complicated story," 1957, from Yiddish (as in a gantse Megillah "a whole megillah"), literally "roll, scroll," collective name of the five Old Testament books appointed to be read on certain feast days, from Hebrew meghillah, from galal "he rolled, unfolded." The slang use is in reference to the length of the text.