opening vs crack

opening and crack both are nouns.

Word	Noun	Adjective	Verb	Adverb
opening	Yes	Yes	No	No
crack	Yes	Yes	Yes	No

As nouns, crack is a hyponym of opening; that is, crack is a word with a more specific, narrower meaning than opening:

As nouns, crack is a hyponym of opening; that is, crack is a word with a more specific, narrower meaning than opening:

opening (noun)	crack (noun)
a recognized sequence of moves at the beginning of a game of chess	the act of cracking something
the act of opening something	a usually brief attempt
becoming open or being made open	a narrow opening
the first of a series of actions	a purified and potent form of cocaine that is smoked rather than snorted; highly addictive
a vacant or unobstructed space that is man-made	a blemish resulting from a break without complete separation of the parts
an entrance equipped with a hatch; especially a passageway between decks of a ship	witty remark
an aperture or hole that opens into a bodily cavity	a sudden sharp noise
a possible alternative	a long narrow cleft
the initial part of the introduction	a long narrow depression in a surface
the first performance (as of a theatrical production)	a chance to do something
a ceremony accompanying the start of some enterprise
an open or empty space in or between things
opportunity especially for employment or promotion

opening (adjective)	crack (adjective)
first or beginning	of the highest quality

opening (verb)	crack (verb)
	break suddenly and abruptly, as under tension
	become fractured; break or crack on the surface only
	break partially but keep its integrity
	cause to become cracked
	reduce (petroleum) to a simpler compound by cracking
	break into simpler molecules by means of heat
	pass through (a barrier)
	tell spontaneously
	hit forcefully; deal a hard blow, making a cracking noise
	suffer a nervous breakdown
	make a sharp sound
	make a very sharp explosive sound
	gain unauthorized access computers with malicious intentions