"I see your windows."
Translation:Widzę twoje okna.
Any noun can "appear" feminine as in end in -a , masculine nouns in gentive, neuter nouns in genitive and plural, some masculine nouns in nominative ( mężczyzna=man, is the most famous)
also as @mixhal noted, polish plural has two genders, different than singular
Masculine personal - masculine nouns that describe persons
not masculine personal - all feminine nouns, all neuter nouns, masculine nouns that do not describe persons.