I study this these sorts of questions in my work as an ethnomusicologist, particularly in the context of Punjabi culture. Speaking generally and customarily, in that cultural context you need (non-vocal) "melody"instruments to have "music." Therefore, singing without instruments is not music (it's singing). And drumming without melodic instruments is drumming. One who sings is not a musicians, s/he is a singer, and one who drums is a drummer, though often called a musician if part of a performance of "music." "Music" does not have a prestigious ring to it, so, contrary to some of the statements above, it is not to rob a skilled singer from some sort of prestige by not calling her/him a musician. Indeed, singers (non-musicians) escape the low status ascribed to musicians, who are by definition "professionals." Before jumping to say that the Punjabi way of thinking is backwards or strange, think of the way a sex worker is a "professional." One would think that she/he is good at sex and should get more respect for being a sex-technician, but that tends not to be the case in Western societies. So, in traditional Punjabi society, one sings or plays certain types of percussion without being labeled musician, and musicians are understood to be the best at what they do yet ascribed a low social status for doing it. One avoids playing instruments as this is what musicians -- people of low status -- do. This is not to say that in India/Pakistan it is impossible to play an instrument as an amateur, but rather that when one does one either does so under the penalty of a certain social judgement or (more frequently) those who do so are individuals whose social privileges allow them to, in a way, transcend the traditional values and exchange them for Western values or live oblivious to social norms... or else to engage another framework of understanding. One of these other frameworks is religion, in which the usual "rules" don't apply to someone if their act is one of religious devotion. As I would explain it, the person playing a musical instrument in the act of / for the purpose of religious devotion is not "creating music" but rather engaging in a devotion and so neither do they receive the stigma of playing music nor the title of musician. A more modern, Western framework is that of art -- where similarly the objective of making "art," especially in an abstract sense and for no monetary compensation, in effect purifies the act of playing music. This person could be called a musician, I think, but is more preferably called an artist.