(v): undergo a change; become different in essence; losing one's or its original nature
(v): make a very sharp explosive sound
(v): make a certain noise or sound
(v): make a sharp sound
(v): make a certain noise or sound
(v): hit forcefully; deal a hard blow, making a cracking noise
(v): deal a blow to, either with the hand or with an instrument
(v): pass through (a barrier)
(v): go across or through
(v): break partially but keep its integrity
(v): break suddenly and abruptly, as under tension
(v): become separated into pieces or fragments
(v): gain unauthorized access computers with malicious intentions
(v): enter someone's (virtual or real) property in an unauthorized manner, usually with the intent to steal or commit a violent act
(v): suffer a nervous breakdown
(v): undergo (as of injuries and illnesses)
(v): tell spontaneously
(v): narrate or give a detailed account of
(v): cause to become cracked
(v): cause to change; make different; cause a transformation
(v): reduce (petroleum) to a simpler compound by cracking
(v): separate (substances) into constituent elements or parts
(v): break into simpler molecules by means of heat
(v): undergo a change; become different in essence; losing one's or its original nature
(n): a long narrow opening
(n): an open or empty space in or between things
(n): a narrow opening
(n): a vacant or unobstructed space that is man-made
(n): a long narrow depression in a surface
(n): a concavity in a surface produced by pressing
(n): a sudden sharp noise
(n): sound of any kind (especially unintelligible or dissonant sound)
(n): a chance to do something
(n): a possibility due to a favorable combination of circumstances
(n): witty remark
(n): a statement that expresses a personal opinion or belief or adds information
(n): a blemish resulting from a break without complete separation of the parts
(n): a mark or flaw that spoils the appearance of something (especially on a person's body)
(n): a purified and potent form of cocaine that is smoked rather than snorted; highly addictive
(n): a narcotic (alkaloid) extracted from coca leaves; used as a surface anesthetic or taken for pleasure; can become powerfully addictive
(n): a usually brief attempt
(n): earnest and conscientious activity intended to do or accomplish something
(n): the act of cracking something
(n): the act of breaking something
(adj): predicate) -- (of the highest quality
(adj): vs. inferior) -- (of high or superior quality or performance
Well, yeah. I just meant in the sense of "fun."
OED says the 16th definition of crack is the connotation in question here: "That which is the subject of boast or eulogy; that which is ‘cracked up’; a horse, player, ship, regiment, etc. of superior excellence..." The first usage in this sense is listed as being in 1637. Unfortunately it doesn't list an etymological source. Hmm.
I think its usage as a noun, e.g. "how's the crack?", does indeed derive from craic. But adjectival use, such as "our crack forensic pathologist" seems likely to have a different etymology (e.g. from crackerjack, perhaps?).
From the Gaelic craic (I think), for "fun."
Contronymic in the sense: excellent vs. flawed.