When something is faint inaudible, it means that it is barely audible or difficult to hear. You could use synonyms such as indistinct, muffled, low-volume, or soft-spoken to describe something that is faint inaudible. The words subtle, muted, hushed, or murmured could also be used to describe something that is barely audible. Other words that may be suitable for describing faint inaudible sounds could include faint whispers, muted murmurs, soft rustles, or dulled tones. Whatever the word choice, it is clear that faint inaudible sounds are delicate and elusive, requiring extra attention and concentration to detect.