/ ˈθɪŋəmi; NAmE / noun
( pl. -ies ) (also thing·ama·bob / ˈθɪŋəməbɒb; NAmE -bɑːb/ thing·uma·jig /ˈθɪŋəmədʒɪg/ thingy ) ( informal ) used to refer to a person or thing whose name you do not know or have forgotten, or which you do not want to mention :
It's one of those thingummies for keeping papers together.
Is thingummy going to be there? You know, that woman from the Sales Department?
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WORD ORIGIN
late 18th cent.: from thing + a meaningless suffix.