plain sailing vs progress

plain sailing and progress both are nouns.

Word	Noun	Adjective	Verb	Adverb
plain sailing	Yes	No	No	No
progress	Yes	No	Yes	No

As nouns, progress is a hypernym of plain sailing; that is, progress is a word with a broader meaning than plain sailing:

Other hypernyms of plain sailing include advance, advancement, forward motion, onward motion, procession, progression.

plain sailing (noun)	progress (noun)
easy unobstructed progress	the act of moving forward (as toward a goal)
	gradual improvement or growth or development
	a movement forward

plain sailing (verb)	progress (verb)
	develop in a positive way
	form or accumulate steadily
	move forward, also in the metaphorical sense