Cassey Is A Form Of Casey, An Irish Personal And Surname Derived From cathasaigh, Meaning “vigilant” And “watchful.” Cassey’s Roots Don’t End There, As The Name Can Also Be Traced As A Nickname For The Greek Cassandra, Meaning “shining Upon Man,” And Catherine, Meaning “pure.” Not As Popular As Its Alternative Cassie, Cassey Grants Baby A Dash Of Originality While Staying Ahead Of The Curve With Its Trendy “y” Spelling. Ideal For The Future-focused Baby With An Appreciation For Antiquity, Cassey Is One To Keep On Your Radar.