Bovine, meaning something has qualities of an ox/cow; bull.
Fecal Matter, obviously is "poop".
When combined, it serves as a lovely way to say "Bullshit."
Also, an abbreviation (BFM) can be used.
Mom: "You're grounded. You should have cleaned your room before you went clubbing."
Me: "Mom, that is bovine fecal matter and you know it."
"Hey, did you hear our football team lost because the ref didn't pay attention? Total BFM."
the clinical way of saying "bullshit"
Person A: "I don't lie, I always tell the truth"
RESPONSE: "that's that bovine fecal matter right there..."