Casey sits next to 3 phonetic neighbors — Kasey, Lacey, and Macy are the closest matches by sound. Most share Casey's Irish-rooted cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"surname origin from Gaelic Mac Caid"
"of the gens Lucia (light)"
"flat-nosed (secondary Greek meaning)"
"military commander, war leader"
"one who shoots with a bow and arrow"
"river that swallows all rivers"
"father of many nations"
"descendant of Bradán (salmon)"
"elm grove"
"of the bean growers (Fabii clan)"
"title of honor, great one"
"good fortune, luck"
"soldier, merciful"
"born of fire"
"son of Karr"
"God has consoled"
"enthusiasm, ardent"
"son of the lion"
"kingly, of royal blood"
Similar sound: These names share phonetic patterns with Casey — similar vowel sounds, consonant clusters, or rhythm.
Rhythm: Casey is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.