I heard "thingy/thingie" very often to refer to "a something". However, I observe it written either way and I don't know what is the correct form.
Dictionary.com redirects "thingie" to "thingy", where the article says:
[thing-ee]
noun, plural thingies.
- Facetious. any small item whose name is unknown or forgotten.
adjective
- of, relating to, or characteristic of inanimate objects.
Then, the Urban Dictionary mentions both: thingy and thingie
n. a non-specific term for anything
Used to describe an object on the spur of the moment when you have a sudden brain fritz and forget exactly what you were gonna say was.
And Wordreference does not find any of them.
What is, then, the proper way to write it?