whirligigs--isn't this a real thing? --any one of several small, usually hand crafted toys that have movement but do nothing (a New England egg beater-- it has the crank and gears, but no "whisks" at the end). they are meant as toys to keep children busy. There is an other one that has a crank the drive a small piston clockwise in a X slot routed in a 3 inch block of wood.
Where as a thingamajig, or thingamabog, is a meaningless word? (or rather a noun that does not name a thing!)
and I guess that is one category of words--nouns that are not the names of a person, place or thing, where as i saw meaningless words as the verbal "fluff" added by careless speakers. yaknow?