prefixes nouns, adjectives or adjectival nouns for intensification; really; truly; totally; completely

what

What?, Huh?

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

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

something

nothing

what is this?

anything; whatever one likes

if you don't mind, if you like, if you're so inclined