afterthought vs turnaround

afterthought and turnaround both are nouns.

Word	Noun	Adjective	Verb	Adverb
afterthought	Yes	No	No	No
turnaround	Yes	No	No	No

As nouns, turnaround is a hypernym of afterthought; that is, turnaround is a word with a broader meaning than afterthought:

Other hypernyms of afterthought include change of mind, flip-flop, reversal, turnabout.

afterthought (noun)	turnaround (noun)
an addition that was not included in the original plan	turning in the opposite direction
thinking again about a choice previously made	act or process of unloading and loading and servicing a vessel or aircraft for a return trip
	an area sufficiently large for a vehicle to turn around
	a decision to reverse an earlier decision
	time need to prepare a vessel or ship for a return trip