Acts 11:3

ἀκροβυστία - acro-plug, extremity stopper, high-point bung

See note at Galatians 2:7.

περιτομῆς (genitive singular of περιτομή) is literally “a cutting around,” from περί “around” + τομή “a cut, incision,” derived from τέμνω “to cut”; the compound is thus semantically transparent and originally denotes a circular or circumferential cutting action, before any later specialized or technical extensions.

So it follows that "uncircumcised" in the Greek would be ἀπερίτμητος formed from the privative prefix ἀ- “not” + περίτμητος “circumcised.” This word is actually used only once in Acts 7:51. This is not the word used here in Acts 11:3 or any of the other 20 verses where most translations render the word "uncircumcised." It is uncertain speculation of a word exclusive to the NT that scholars could only give opinions on. The compound ἀκροβυστία has nothing signifying "cutting" nor "covering" and thus the signification of "uncircumcised" is forced onto it.