Question: what is the idiomatic expression of horse?
Answer: as strong as a horse/ox. - very strong. ...  as stubborn as a mule. - very stubborn. ...  back the wrong horse. - to support someone or something that cannot or does not win or succeed. ...  beat a dead horse. ...  bet on the wrong horse. ...  by shank's mare. ...  champ/chomp at the bit. ...  change horses in midstream.