It's Irish for 'Soldiers of Destiny'

A closer approximation would be "Faw-ill", emphasis on first "syllable", but as a diphthong sound that almost ends up sounding like a shortened "eel". In other words, the "a" sound starts out sounding like it does in "fall", but ends up a hair away from "e" in "eel".

That's how I'd say it with a Gaeltacht accent in Galway. People who learned Irish from a non-native speaker or a different area of the country will probably disagree.