To be long in the tooth is to be old, either in age or simply out of date. This phrase originated with horses, whose teeth continue to grow and be worn down throughout their life, so that by looking at their teeth one can guess at the horses’ age. It is commonly used in the financial and technological worlds where items can be dated very quickly.
A related phrase is don’t look a gift horse in the mouth, which means if someone is giving you a gift, don’t complain about it. It began as a proverb and was written in English for the first time in 1546, no man ought to look a given horse in the mouth. The phrase appears in Latin in 400 AD, translating as never inspect the teeth of a given horse.
Examples
Stocks, which have had a great run since March 2009, look a bit long in the tooth, and there are pervasive worries about an impending correction. [Barrons]
A patchwork of free agents and long-time, long-in-the-tooth starters taking up nearly as many roster spots as their supposed up-and-coming talent. [Memphis Daily News]
“The bull market is getting long in the tooth,” Rich Weiss, the Mountain View, California-based senior portfolio manager for American Century Investment, said by phone. [BNN]
While the offer is a great gesture from Sony, it does seem a bit pointless when a majority of the games being purchased on the PlayStation 4 require PlayStation Plus, and not having it defeats the purpose of owning those games. Of course, there is always the saying ‘don’t look a gift horse in the mouth’, so best not say no to this deal. [Aus Gamers]