We all know what that means when we hear it even though we are willing to be pretty broad about our definition.
We mean someone that very closely agrees with and follows a particular belief system.
Sometimes it can be rather trivial or even in jest like "a disciple of garlic" or some similar thing. And in that case we know that the "disciple" doesn't mean that the particular thing applies to his entire life.
On the other hand when we talk of being a disciple of Jesus Christ we know that the person is in fact speaking about the entirety of his life: thought, deed, faith, everything.
Discipleship always involves learning or at least I cannot imagine otherwise. If you are not learning about your master then how can you really claim to be a disciple? Also I was thinking that this element of discipleship means that it is never "blind" allegiance. In fact the novice disciple is recognized as being the poorer disciple exactly because he or she knows less.
Discipleship always involves the recognition that the master is the master. At least in following Jesus the student never becomes the master.
Discipleship always involves actually following in action as well as knowledge. Just knowing something and doing nothing is certainly no better and probably much worse than not knowing at all.
Discipleship definitely involves being. One either is or isn't a disciple. There's no middle ground. You just can't be a little bit of a disciple. Nor is it correct to say someone is more of a disciple than someone else.
The one verse that always comes to mind when I think of discipleship is John 5:30:
I can do nothing on My own initiative As I hear, I judge; and My judgment is just, because I do not seek My own will, but the will of Him who sent Me.