What does it mean: "a move operation is never implicitly defined as a deleted function" in C++Primer 5th edition?

Question

I am reading "C++ Primer", 5th edition. And I can not understand the following passage. It comes from page 538~539.

Unlike the copy operations, a move operation is never implicitly defined as a deleted function.

Never? But aren't all the definitions mentioned later implicit?

However, if we explicitly ask the compiler to generate a move operation by using = default (§ 7.1.4, p. 264), and the compiler is unable to move all the members, then the move operation will be defined as deleted. With one important exception, the rules for when a synthesized move operation is defined as deleted are analogous to those for the copy operations (§ 13.1.6, p. 508):

• Unlike the copy constructor, the move constructor is defined as deleted if the class has a member that defines its own copy constructor but does not also define a move constructor, or if the class has a member that doesn’t define its own copy operations and for which the compiler is unable to synthesize a move constructor. Similarly for move-assignment.

• The move constructor or move-assignment operator is defined as deleted if the class has a member whose own move constructor or move-assignment operator is deleted or inaccessible.

• Like the copy constructor, the move constructor is defined as deleted if the destructor is deleted or inaccessible.

• Like the copy-assignment operator, the move-assignment operator is defined as deleted if the class has a const or reference member.