noun

• (slang) An unfavorable card or token, or undesirable or worthless item used as a prize in a contest or game show (such as Let's Make a Deal).
  "There will always be two doors that hold zonks, so regardless of whether you initially chose the grand prize or a zonk, Monty will always be able to show you a zonk not chosen."
• (slang) The feeling of a drug taking hold.
• (slang) A cigarette hand-rolled from tobacco and cannabis.

verb

• (transitive, slang) To hit hard .
• (transitive, slang) To make (someone) sleepy or delirious, to put into a stupor .
• (intransitive, slang, usually followed by “out”) To become exhausted, sleepy or delirious.
  "After two hours of studying, I zonked out."