Hilary sits next to 4 phonetic neighbors — Hillary, Hilary, and Ellery are the closest matches by sound. Most share Hilary's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"cheerful, merry, joyful"
"flower garland, grace"
"heavenly, of the sky"
"modern invented name"
"shining, bright"
"like coral, sea-born beauty"
"graceful, favored by God"
"gatherer, collector"
"halo of the moon, moonlit"
"unfortunate, unhappy"
"azalea flower"
"victory of the people"
"beautiful serpent (wisdom)"
"courageous, valiant"
"modern coinage with divine suffix"
"beautiful rose (folk etymology)"
"resolute protector"
"holding firm to goodness (feminine of Darius)"
"snow"
Similar sound: These names share phonetic patterns with Hilary — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Latin origins, giving them the same cultural heritage as Hilary.
Rhythm: Hilary is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.