For further clarity, Wayne Grudem, in his Systematic Theology, defines inerrancy like this:
The inerrancy of Scripture means that Scripture in the original manuscripts does not affirm anything that is contrary to fact.Grudem also, after describing challenges to inerrancy, provides four problems of denying the doctrine. I find the 3rd to be the strongest.
1. If we deny inerrancy, a serious moral problem confronts us: may we imitate God and intentionally lie in small matters?
2. If inerrancy is denied, we being to wonder if we can really trust God in anything he says.
3. If we deny inerrancy, we essentially make our own human minds a higher standard of truth than God's Word itself.
4. If we deny inerrancy, then we must also say that the Bible is wrong not only in minor details but in some of its doctrines as well.