old hat

old hat · noun, adjective¹

From old + hat, possibly a reference to something familiar and well-used. The Oxford English Dictionary suggests a connection to German alter Hut (“something familiar and hackneyed”, noun, literally “old hat”).

old hat · noun²

From old + hat, the significance being unknown.

First known use, by meaning

• from early 20th c. Something regarded as very familiar and unoriginal, hackneyed, or out of date.
• from mid 20th c. Very familiar and unoriginal; common, hackneyed, out of date.