The phrase "old warhorse" refers to someone who is experienced, skilled, or knowledgeable in a particular field or activity due to having a lot of practice or years of involvement. Full definition
We take a look at how the tablet compares against old warhorses from Samsung and Google, i.e. the Galaxy Tab S2 9.7 and the Google Pixel C. (techtimes.com)
The grand old warhorse of the Labour Party, Roy Hattersley, would disagree. (totalpolitics.com)
Then it's back to London for some very bad news: MI6's Double - 0 program is under threat thanks to the machinations of creepy surveillance agent C (Andrew Scott), leaving old warhorses like M (Ralph Fiennes), Q (Ben Whishaw) and Bond himself facing the scrapheap. (timeout.com)