play a part, perform

sudden / abrupt / unexpected / instant

sudden, abrupt, unexpected

Short for 俄狂言 (niwaka kyōgen, “a farce; an impromptu comic interlude during a Noh play”). / (by extension) any impromptu joke, witticism, or pun

sudden, abrupt, unexpected, improvised, offhand / suddenly serious (said of an illness; most often in the construction にわかになる (niwaka ni naru)) / temporary, makeshift, impermanent, ad hoc

ancient times, a very long time ago

the past, old times / ancient

(honorific) festival

festival / ceremonial

once (in the indeterminate past)