What is the meaning of uncircumcised in the bible?

Strictly, uncircumcised means still having the prepuce, or foreskin, of one's penis. As a practical matter, the term meant "Not a Jew"; "Not one of us"; an alien, barabarian or no-good person. This is the way David uses it when he asks about Goliath, "Who is this uncircumcised Philistine?"