Find the word definition

Wiktionary
and the horse you rode in on

phr. 1 (non-gloss definition: Intensifier). 2 (non-gloss definition: Euphemistic shortening of "fuck you and the horse you rode in on")

Wikipedia
And the Horse You Rode in On

And the Horse You Rode in On is the seventh solo studio album by Australian singer/songwriter James Reyne released on 14 March 2005. It's an acoustic recording of songs taken from his earlier solo work and Australian Crawl songs. It includes two new tracks. Later digital editions renamed this album as Greatest Hits Acoustic.

Usage examples of "and the horse you rode in on".

Well, fuck you and the horse you rode in on - Admiral, sir, his face managed to communicate quite clearly.

Your words are fine, but your tone says fuck you and the horse you rode in on.