Sir sits next to 3 phonetic neighbors — Sur, Ser, and Sire are the closest matches by sound. Most share Sir's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"lord, master"
"divine strength"
"buck's meadow, deer clearing"
"god's field, divine meadow"
"skilled craftsman"
"boar-friend, warrior companion"
"lion-hearted, brave"
"gift of Yahweh"
"wolf, wild hunter"
"farmer, estate steward"
"follower of Calvin (in Protestant tradition)"
"most high, exalted one"
"God helps"
"maker of cords and ropes"
"God is gracious"
"holy, sacred one of God"
"modern invented spelling"
"one who serves"
"old settlement"
"vigilant in war"
"white meadow"
Similar sound: These names share phonetic patterns with Sir — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old French origins, giving them the same cultural heritage as Sir.
Rhythm: Sir is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.