Marcy sits next to 4 phonetic neighbors — Darcy, Nancy, and Stacy are the closest matches by sound. Most share Marcy's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"of Mars; warlike"
"spoken word, narrative"
"relating to the lyre, musical, lyrical"
"star"
"lake, pool (Lynn element)"
"God is my refuge"
"gift of God"
"king's meadow, royal clearing"
"white, pure"
"Geirr's island (Old Norse place name)"
"star"
"from Lucania (southern Italy)"
"high clearing in woodland"
"gift, feminine grace"
"river of light"
"sweet water, fair river"
"gentle one"
"rival, eager"
"new star, bright beginning"
"weary, delicate"
"one strength, unique strength"
Similar sound: These names share phonetic patterns with Marcy — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Latin origins, giving them the same cultural heritage as Marcy.
Rhythm: Marcy is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.