piffle vs bunk

piffle and bunk both are nouns.

Word	Noun	Adjective	Verb	Adverb
piffle	Yes	No	Yes	No
bunk	Yes	No	Yes	No

As nouns, bunk is a hypernym of piffle; that is, bunk is a word with a broader meaning than piffle:

Other hypernyms of piffle include hokum, meaninglessness, nonsense, nonsensicality.

piffle (noun)	bunk (noun)
trivial nonsense	a bed on a ship or train; usually in tiers
	a rough bed (as at a campsite)
	beds built one above the other
	a long trough for feeding cattle
	unacceptable behavior (especially ludicrously false statements)
	a message that seems to convey no meaning

piffle (verb)	bunk (verb)
act in a trivial or ineffective way	flee; take to one's heels; cut and run
speak (about unimportant matters) rapidly and incessantly	provide with a bunk
	avoid paying