The saying 'your the cats meow' means you are a highly admired person. Now that I like.
The saying 'you are the cats pajamas' means the same as 'you are the cats meow'. They are slang from the 1920's a very colorful time in our history.
Didn't think I could find a cat in pajamas did you?
The 1920's saw prohibition which allowed the rise of organized crime through bootlegging. But it was also a wonderful time to be growing up in the United States.
The 20's gave rise to so many fun slang sayings like:
~All Wet - describes an erroneous idea or individual, as in, "he's all wet."
~Attaboy - well done!; also Attagirl!
~Bank's Closed - no kissing or making out - i.e. - "Sorry, Mac, the bank's closed."
~Bluenose - An excessively puritanical person, a prude, Creator of "the Blue Nozzle Curse."
~Bronx Cheer - A loud spluttering noise, used to indicate disapproval. Same as raspberry . One of my personal favorites, lol.
~Fire extinguisher - a chaperon
~Flat Tire - A dull witted, insipid, disappointing date. Same as pill, pickle, drag, rag, oilcan
~Handcuff - an engagement ring
~Iron - a motorcycle
~Sinker - a doughnut
~Upchuck - To vomit when one has drunk too much
~You slay me - that's funny
There is an entire website dedicated to 1920's sayings; http://local.aaca.org/bntc/slang/slang.htm.
The 1920's always remind me of my mom and dad who were born in 1919. They met on Marcy Avenue, Williamsburg, Brooklyn, NY when they were about 6 years old when mom ran dad down when she was trying to learn to roller skate. From that day on they were constant companions never dating anyone else in their lives.
Funny what memories old sayings bring back.