Kwan; whatchamacallit (lit. what-you-may-call-it); thingamajig (a word used to designate s.t. for which one cannot remember the name).
It is affixed with the appropriate verbal or nominal affixes of the word it is substituted for.
Where did you put the what-you-may-call-it?
Anuhanun ko' iyan.
Kwan (do) that (not said what).