Also see Inerrancy and dynamic infallibility. Honestly, some people use inerrancy and infallibility interchangeably, so it can be confusing.
It defines the Scripture as reliable and trustworthy to those who turn to it in search of God's truth. As a source of truth, the Bible is indefectable and cannot fall away or defect from the standard of truth. It will never fail or deceive anyone who trusts it.
Infallibility is more concerned with personal knowledge of God and assurance of salvation. Those who believe in an infallible Bible do not necessarily believe in an inerrant Bible.
(The Origin of the Bible: Newly Updated by F. F. Bruce, J. I. Packer, Philip W. Comfort, and Carl F. H. Henry, 2020. The Inerrancy and Infallibility of the Bible by Harold O. J. Brown. Page 38-39)
Beliefs by groups
Infallible has a long pedigree among Reformers, including the Westminster Confession ('infallible truth'). ('Fundamentalism' and the Word of God: Some Evangelical Principles by J. I. Packer, 1958, Page 95-96)
Evangelicals acknowledge the Bible is human as well as divine.
Karl Barth maintains to err is human, so a human book will contain errors even while divine. He is cautious to attribute any specific errors to the Bible, yet he argues error cannot be excluded on principle.
Nonevangelical scholars reject both infallibility and inerrancy and see no merit in separating them.
(The Origin of the Bible: Newly Updated by F. F. Bruce, J. I. Packer, Philip W. Comfort, and Carl F. H. Henry, 2020. Pages 38-39.)
The medieval church asserted verbal inspiration and infallibility. Martin Luther and other Protestant Reformers had no need to exalt the infallibility of Scripture, which the Roman Catholic Church accepted. They tried to combat Catholic exaltation of tradition as an equal or superior to Scripture.
(The Origin of the Bible: Newly Updated by F. F. Bruce, J. I. Packer, Philip W. Comfort, and Carl F. H. Henry, 2020. Pages 42-43.)