IPA: /ˈfɔːltləs/
KK: /ˈfɔltləs/
Being completely free from mistakes or imperfections; perfect.
Her performance in the play was faultless, impressing everyone in the audience.
Faultless → It is formed from "fault" (from Old French *faulte*, meaning a defect or error) and "-less" (meaning without). The word "faultless" means without fault or error.
Think of being 'without' ('-less') any 'defect' ('fault') — that's why faultless means perfect or without mistakes.