Cinthia sits next to 4 phonetic neighbors — Cynthia, Synthia, and Lucinda are the closest matches by sound. Most share Cinthia's Spanish-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"woman from Mount Kynthos, moon goddess"
"western waterfall"
"gazelle (Aramaic equivalent — this is the translation of Tabitha)"
"big happiness, great light"
"God is gracious (Jo) + lake or waterfall (Lynn)"
"wished-for child + of noble kind"
"variant of Sheila (blind one, or heavenly)"
"heavenly, elevated one"
"dawn, daybreak"
"royal woodland clearing"
"The other Aenor (foreign)"
"grace, favor"
"cushion (archaic interpretation)"
"state of well-being"
"pure, beautiful"
"son of Maud, mighty in battle"
"from Britain, a Briton"
"Desired, longed for"
"hermitage meadow, woodland clearing"
"celestial, divine"
"island of Geirr (Old Norse place name)"
Similar sound: These names share phonetic patterns with Cinthia — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek origins, giving them the same cultural heritage as Cinthia.
Rhythm: Cinthia is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.