
1) Behind the times 2) Certainly not modern 3) Commonplace 4) Dated 5) Hackneyed 6) Like the outmoded trilby 7) No longer in fashion 8) No longer in style 9) No longer interesting 10) Nothing new 11) Out of date 12) Outdated 13) Outmoded 14) Passé 15) Quite trite 16) Quite trite and familiar 17) Rather stale
Found on
https://www.crosswordclues.com/clue/old-hat
[horse] Old Hat (foaled in Kentucky in 1959), was an American Thoroughbred racing mare by Boston Doge out of Fine Feathers (1 win in 39 starts), whose sire was Double Jay. On his topline, Double Jay`s grandsire was Black Toney. On his bottomline, it was Whisk Broom. Her sire, Boston Doge, was a multiple stakes winner. Out of 18 starts, he w...
Found on
http://en.wikipedia.org/wiki/Old_Hat_(horse)

Old hat is British slang for old fashioned.
Found on
http://www.probertencyclopaedia.com/browse/ZO.HTM
No exact match found.