What is the Etymology of “Grager”?
Grager is the noisemaker we use on Purim during the Megila when Haman's name is read.
According to The Merriam Webster Dictionary online it is from the Polish word grzegarz, meaning rattle.
My knowledge of the polish language is non-existent, but the dictionaries I found online (such as this one) didn't translate rattle that way. See here for many different polish words for the word rattle.
Google Translate has tons of different words for the word rattle.
You can listen to the pronunciation of Polish words here.
Sounds like an onomatopoeia to me.