Qui: pronoun --> subject (Who)
sine: preposition (without)
peccato: noun peccatum/-i (sin)
est: verb, third person singular, present "sum/es/fui/esse" (is)
vestrum: adjective (among you)
primus: adjective "primus/-a/-um" nominative singular (first)
lapidem: noun "lapis/lapidis" accusative singular (stone)
mittat: verb; conjunctive present, 3rd person singular "mitto/mittis/misi/missum/mittere" (throw)
Literal translation:
Who among you is without sin, threw a stone first
It's a famous Bible quote, which has many translations who fit the context better, like "He who is without sin among you, let him be the first to throw a stone at her"
I'm sure you'll find many interpretations online that fit anything you need.
I hope this helps, even though English isn't my first language :)