12 Q. Who are infidels?
A. Infidels are those who have not been baptised and do not believe in Jesus Christ, because they either believe in and worship false gods as idolaters do, or though admitting one true God, they do not believe in the Messiah, neither as already come in the Person of Jesus Christ, nor as to come; for instance, Mohammedans and the like.
Source of text: CATECHISM OF SAINT PIUS X: The Ninth Article of the Creed, Those Outside the Communion of Saints, 12 Q. Who are infidels?; sensusfidelium.us/…he-ninth-article-of-the-creed/ ; catholicbook.com/AgredaCD/PiusX/pcreed09.htm
72. But in this battle joined by the powers of darkness against the very idea of Divinity, it is Our fond hope that, besides the host which glories in the name of Christ, all those - and they comprise the overwhelming majority of mankind, - who still believe in God and pay Him homage may take a decisive part.
Source of text: Encyclical "Divini Redemtoris" 72; vatican.va/…370319_divini-redemptoris.html
16. Nor can We pass over in silence the profound impression of heartfelt gratitude made on Us by the good wishes of those who, though not belonging to the visible body of the Catholic Church, have given noble and sincere expression to their appreciation of all that unites them to Us in love for the Person of Christ or in belief in God. We wish to express Our gratitude to them all. We entrust them one and all to the protection and to the guidance of the Lord and We assure them solemnly that one thought only fills Our mind: to imitate the example of the Good Shepherd in order to bring true happiness to all men: "that they may have life, and may have it more abundantly" (Saint John x. 10).
Source of text: Encykclical "Summi Pontificatus" 16; vatican.va/…101939_summi-pontificatus.html