Definition of "watertight" []

• So tightly made that water cannot enter or escape. (adjective)
• Having no flaws or loopholes; impossible to fault, refute, or evade: a watertight alibi; a watertight contract. (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.

• "What an absurd and anomalous position, but the result is very serious for it means that as we are all separated by these artificial barriers which we have erected, there is a danger of our working and thinking in watertight compartments."
• "It is a mistake to imagine that war aims, strategy, propaganda and industrial organisation exist in watertight compartments."
• "This system, of course, is not watertight, which is why, meanwhile, we have decided to start using body scanners on flights to the States."