Definition of "make-or-break" [make-or-break]

• Resulting in great success or utter failure: a make-or-break investment plan. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Which is why he's not obsessing over the fact that "Thor" has been described as make-or-break for his directing career."
• "High-level climate talks, due to start in Durban on November 28 under the UN Framework Convention on Climate Change, are being called a make-or-break meeting for legally binding carbon emission reduction targets. ..."
• "Shaida Mohammad Abdali, Mr. Karzai's deputy national security adviser, recently called civilian casualties a "make-or-break" issue."