Words similar to tip-off

Example sentences for: tip-off

How can you use “tip-off” in a sentence? Here are some example sentences to help you improve your vocabulary:

It is sometimes difficult to determine if it's real or if it's Memorex, though build, voice, and the hint of a beard can sometimes be a tip-off.
The tip-off is that he notes (in the seventh paragraph) that there are "21 such shootings annually"--not too statistically significant, given that there are nearly 20,000 gun deaths per year.
Another tip-off is that Hatfield doesn't discuss his three high-level, inside-the-enemy-camp sources in the body of the book, which was already in galleys when the author made his "discovery."