sail vs change course

sail is a noun but change course is not a noun.

Word	Noun	Adjective	Verb	Adverb
sail	Yes	No	Yes	No
change course	No	No	Yes	No

As verbs, change course is a hyponym of sail; that is, change course is a word with a more specific, narrower meaning than sail:

Other hyponyms of sail include run, luff, point, weather, beat, rack, scud, outpoint, tack, wear round, wear ship, gybe, jib, jibe.

sail (noun)	change course (noun)
an ocean trip taken for pleasure
a large piece of fabric (usually canvas fabric) by means of which wind is used to propel a sailing vessel
any structure that resembles a sail

sail (verb)	change course (verb)
travel on water propelled by wind	shift from one side of the ship to the other
move with sweeping, effortless, gliding motions
travel on water propelled by wind or by other means
traverse or travel on (a body of water)