Likely to cause an accident: a breakneck curve. (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.
Use "breakneck" in a sentence
"The desire to pass such a huge plan of enormous financial proportions in breakneck time is both arrogant and dangerous."
"The Warriors closed to 38-27 after one quarter and 73-64 at halftime as the teams raced up and down the court in breakneck fashion."
"Combining a fascinating world with a population of interesting characters and a pace best described as breakneck, culminating with nail-biting action and a surprising denouement, the first novel in the Clockwork Century grabs your attention and refuses to let go."