What? What did you say?

whatchamacallit, X

project management

(archaic) second-person personal pronoun: you

human / person / people / individual / man / woman / someone

what is this?

what

what number, how many (used with a counter) / (used with も) many (used with a counter)

What?, Huh?

what / that thing (used in place of words you can't remember at the moment.)