Noun

• S: (n) crack, cleft, crevice, fissure, scissure (a long narrow opening)
• S: (n) gap, crack (a narrow opening) "he opened the window a crack"
• S: (n) crevice, cranny, crack, fissure, chap (a long narrow depression in a surface)
• S: (n) crack, cracking, snap (a sudden sharp noise) "the crack of a whip"; "he heard the cracking of the ice"; "he can hear the snap of a twig"
• S: (n) shot, crack (a chance to do something) "he wanted a shot at the champion"
• S: (n) wisecrack, crack, sally, quip (witty remark)
• S: (n) crack (a blemish resulting from a break without complete separation of the parts) "there was a crack in the mirror"
• S: (n) crack, crack cocaine, tornado (a purified and potent form of cocaine that is smoked rather than snorted; highly addictive)
• S: (n) crack, fling, go, pass, whirl, offer (a usually brief attempt) "he took a crack at it"; "I gave it a whirl"
• S: (n) fracture, crack, cracking (the act of cracking something)

Verb

• S: (v) crack, check, break (become fractured; break or crack on the surface only) "The glass cracked when it was heated"
• S: (v) crack (make a very sharp explosive sound) "His gun cracked"
• S: (v) snap, crack (make a sharp sound) "his fingers snapped"
• S: (v) crack (hit forcefully; deal a hard blow, making a cracking noise) "The teacher cracked him across the face with a ruler"
• S: (v) break through, crack (pass through (a barrier)) "Registrations cracked through the 30,000 mark in the county"
• S: (v) crack (break partially but keep its integrity) "The glass cracked"
• S: (v) snap, crack (break suddenly and abruptly, as under tension) "The pipe snapped"
• S: (v) crack (gain unauthorized access computers with malicious intentions) "she cracked my password"; "crack a safe"
• S: (v) crack up, crack, crock up, break up, collapse (suffer a nervous breakdown)
• S: (v) crack (tell spontaneously) "crack a joke"
• S: (v) crack (cause to become cracked) "heat and light cracked the back of the leather chair"
• S: (v) crack (reduce (petroleum) to a simpler compound by cracking)
• S: (v) crack (break into simpler molecules by means of heat) "The petroleum cracked"

Adjective

• S: (adj) ace, A-one, crack, first-rate, super, tiptop, topnotch, top-notch, tops (of the highest quality) "an ace reporter"; "a crack shot"; "a first-rate golfer"; "a super party"; "played top-notch tennis"; "an athlete in tiptop condition"; "she is absolutely tops"