old dog
Preserved but no longer current.
A knowing blade, an experienced person. Butler uses the phrase, Hudibras, part ii. canto iii. 208, where it was said of Sidrophel, "And was OLD DOG at physiology." An Irish proverb says, "OLD DOG for hard road," meaning that it requires an experienced person to execute a difficult undertaking.
Era: ca. 1874 (Victorian)
Sources & notes
Historical definition reproduced from Hotten’s The Slang Dictionary (1874, public domain; Project Gutenberg #42108, retrieved 2026-07-31). Reflects the attitudes of its era.
Common questions
What does “old dog” mean?
A knowing blade, an experienced person. Butler uses the phrase, Hudibras, part ii. canto iii. 208, where it was said of Sidrophel, "And was OLD DOG at physiology." An Irish proverb says, "OLD DOG for hard road," meaning that it requires an experienced person to execute a difficult undertaking.
Is “old dog” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.