Search the title for the rest of the series - a while back.
Further conversation with a friend, never posted, but drafted.
Parental advisory - rough language implied below...
Paul used the Greek equivalent of "bulls____" to emphasize the contrast between worldly gains and knowing Christ (Phil 3:8)
Assuming it isn't garbage, but human waste, your terminology may be right, but we also have words like "waste" to refer to this. Maybe you've studied this, and it is the vulgar use instead of the polite one. If that is the case, I still don't see a problem. The problem is with our wacky verbal values these days, making as big a deal over "sh__" as we do over "God d___ it" or "Jesus Christ" as a flippant expression of surprise, alarm or disgust. Honestly, I don't know that I would always consider the verbalization of "sh-t" as a sin. Almost never wise or helpful, either, of course, but I think its use is certainly edifying in Phil 3:8! The principle is that we too easily equate victorian, discrete politeness with Biblical morality. "Righteousness" is not defined as "nice," or "polite." The two are not always the same. For more examples look in the KJV at 1 Sam 25:22, 34; 1 Kings 14:10; 16:11; 21:21; 2 Kings 9:8; or in the NIV at Ezekiel 23:20, or much of the Song of Solomon.
1 Samuel includes a quote from Saul saying their equivalent of “son of a b____” (20:30)
Many principles of the previous answer apply, but also Saul's sin is showing in his unjustified and abusive anger toward his innocent son.
On Paul's use of vulgarity, I agree that our concept of unacceptable language is flawed in that we tolerate misuse of God's name and recoil in horror at the "sh" word or even the "f" word. Biblically speaking, vulgar language doesn't come close to the misuse of God's name in the degree of sinfulness. I include this and Saul's words in the list to try and point out our simplistic and Biblically flawed, yet supposedly air-tight notions of sin. Christians I know would bristle at that language, but why would the Biblical writers document it as such instead of saying that Saul cursed Jonathan?
To give us a picture of Saul's out of control character? Don't know exactly.