My thoughts...
One - United, on body, one mind of Christ; one Holy Spirit guiding the Church; the body of Christ cannot be divided
Holy - Called to sanctity and following God, set apart, a "peculiar people," called to be virtuous and seek God with all our hearts
Catholic - Whole and entire, not lacking anything, wherever two or three are gathered as the Church, under their bishop, in the Church
Apostolic - Having an apostolic character, derived from and continuing in apostolic authority, continuity and teachings
+1