Learning = changing in a way that allows you to solve (a certain class of) problems more efficiently (on average).
Not learning = either not changing, or changing in a way that does not make you more efficient at solving problems.
(Note: I am saying “on average”, because… suppose your original algorithm for solving math problems is simply yelling “five!” regardless of the problem. Now you learn math, and it makes you better at solving math problems in general… but it makes you slower at solving those problems where “five” actually happens to be the correct answer.)
Learning = changing in a way that allows you to solve (a certain class of) problems more efficiently (on average).
Not learning = either not changing, or changing in a way that does not make you more efficient at solving problems.
(Note: I am saying “on average”, because… suppose your original algorithm for solving math problems is simply yelling “five!” regardless of the problem. Now you learn math, and it makes you better at solving math problems in general… but it makes you slower at solving those problems where “five” actually happens to be the correct answer.)