Cassidy sits next to 4 phonetic neighbors — Cassidy, Cassie, and Cassius are the closest matches by sound. Most share Cassidy's Irish-rooted cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"curly-haired"
"maker of cords and ropes"
"one who sets free"
"warrior people (Cree)"
"prophet, one who prophesies"
"may God protect"
"friend of warriors"
"brave one, bold and courageous"
"of the forest, woodland"
"universe, cosmos"
"battlefield (poetic extension)"
"resolute protector (from Liam/William)"
"shining with glory"
"belonging to God"
"son of a nobleman (variant interpretation)"
"son of the prince (elaborated form)"
"little fire"
"nobleman, earl"
"third in line"
"happy estate"
"lake meadow"
Similar sound: These names share phonetic patterns with Cassidy — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Irish Gaelic origins, giving them the same cultural heritage as Cassidy.
Rhythm: Cassidy is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.