Undiscernibly is a term that means in a way that cannot be perceived or detected. There are several synonyms for this word, including invisibly, imperceptibly, and indiscernibly. These words all describe something that is so subtle or faint that it cannot be easily noticed or discerned. Other related terms include secretly, clandestinely, unobtrusively, and surreptitiously. When writing, it is important to choose the right words to accurately convey the intended meaning and tone of the piece. Using synonyms for undiscernibly can help to add variety and nuance to your writing while still clearly communicating your message.