This from the CDF provides some insight:
indifferentism, noun: the belief that differences of religious belief are of no importance.
proselytize, verb: [with object] convert or attempt to convert (someone) from one religion, belief, or opinion to another: the program did have a tremendous evangelical effect, proselytizing many
Doctrinal Note On Some Aspects Of Evangelization (2007)
Congregation for the Doctrine of the Faith
III. Some ecclesiological implications
However, the Church’s “missionary proclamation is endangered today by relativistic theories which seek to justify religious pluralism, not only de facto but also *de iure *(or in principle)”. For a long time, the reason for evangelization has not been clear to many among the Catholic faithful. It is even stated that the claim to have received the gift of the fullness of God’s revelation masks an attitude of intolerance and a danger to peace.
Those who make such claims are overlooking the fact that the fullness of the gift of truth, which God makes by revealing himself to man, respects the freedom which he himself created as an indelible mark of human nature: a freedom which is not indifference, but which is rather directed towards truth. This kind of respect is a requirement of the Catholic faith itself and of the love of Christ; it is a constitutive element of evangelization and, therefore, a good which is to be promoted inseparably with the commitment to making the fullness of salvation, which God offers to the human race in the Church, known and freely embraced.
IV. Some ecumenical implications
In addition, there is evangelization in countries where non-Catholic Christians live, including those with an ancient Christian tradition and culture. In this context, what is required is both true respect for the tradition and spiritual riches of such countries as well as a sincere spirit of cooperation. Catholics, “avoiding every form of indifferentism or confusion, as well as senseless rivalry, through a common profession of faith in God and in Jesus Christ before all peoples – insofar as this is possible – may collaborate with their separated brethren in social, cultural, technical and religious matters in accordance with the Decree on Ecumenism”.
Ecumenism does not have only an institutional dimension aimed at “making the partial communion existing between Christians grow towards full communion in truth and charity”. It is also the task of every member of the faithful, above all by means of prayer, penance, study and cooperation. Everywhere and always, each Catholic has the right and the duty to give the witness and the full proclamation of his faith. With non-Catholic Christians, Catholics must enter into a respectful dialogue of charity and truth, a dialogue which is not only an exchange of ideas, but also of gifts, in order that the fullness of the means of salvation can be offered to one’s partners in dialogue. In this way, they are led to an ever deeper conversion to Christ.
In this connection, it needs also to be recalled that if a non-Catholic Christian, for reasons of conscience and having been convinced of Catholic truth, asks to enter into the full communion of the Catholic Church, this is to be respected as the work of the Holy Spirit and as an expression of freedom of conscience and of religion. In such a case, it would not be a question of proselytism in the negative sense that has been attributed to this term.
 Second Vatican Council, Decree Ad gentes, 15.
 John Paul II, Encyclical Letter Ut unum sint (25 May 1995), 14: AAS 87 (1995), 929.
 Cf. ibidem, 28: AAS 87 (1995), 939.
 Cf. Second Vatican Council, Decree Unitatis redintegratio, 3 and 5.
 The term proselytism originated in the context of Judaism, in which the term proselyte referred to someone who, coming from the gentiles, had passed into the Chosen People. So too, in the Christian context, the term proselytism was often used as a synonym for missionary activity. More recently, however, the term has taken on a negative connotation, to mean the promotion of a religion by using means, and for motives, contrary to the spirit of the Gospel; that is, which do not safeguard the freedom and dignity of the human person. It is in this sense that the term proselytism is understood in the context of the ecumenical movement: cf. The Joint Working Group between the Catholic Church and the World Council of Churches, “The Challenge of Proselytism and the Calling to Common Witness” (1995).