> What is "skill entropy"

Skill entropy is a result of reliance on tools to perform tasks which otherwise would contribute to and/or reinforce a person's ability to master same. Without exercising one's acquired learning, skills can quickly fade.

For example, an argument can be made that spellcheckers commonly available in programs degrade people's ability to spell correctly without this assistance (such as when using pen and paper).

I did mean "atrophy" as others mentioned.

atrophy?

They think it's a smart way to say that the o.p. is dumb.