Rowdy sits next to 3 phonetic neighbors — Brody, Cody, and Woody are the closest matches by sound. Most share Rowdy's American English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"boisterous, spirited, lively"
"wealth, fortune"
"wise friend"
"strength, permanence"
"case, container (via Old French)"
"may God give increase"
"fragrant, sweet-smelling"
"famous wolf"
"continuous improvement"
"genuine, authentic, honest"
"God is gracious"
"new house"
"land of purple dye"
"gift of God"
"the cleansing one"
"slender, bright-headed"
"son of Cole"
"powerful ruler of the home"
"messenger"
"chief desire"
Similar sound: These names share phonetic patterns with Rowdy — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have American English origins, giving them the same cultural heritage as Rowdy.
Rhythm: Rowdy is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.