frobnitz vs whatchamacallit

frobnitz

noun
  • Synonym of gizmo 

whatchamacallit

noun
  • A metasyntactic term used for any object whose actual name the speaker does not know or cannot remember; a doodad, gizmo, thingamajig, thingy. 

How often have the words frobnitz and whatchamacallit occurred in a corpus of books? (source: Google Ngram Viewer )