A musically inclined person who, instead of being a showman (like most guitarists, but not all) is more the pure musician along with the drummer, the pianist, and the mandolin
player, the "musician in the group.
But the main job (this, coming from a bass
player) is to translate the languages between the guitarist and the drummer, for they speak two totally different languages.
And popular to popular opinion, the bass
player does not usually create the rhythm or even state it for the guitarist to play along with, it is the drummer that does that in most circumstances. The bass
player in most occasions adds to that rhythm and makes it more complex, or creates a bas(s)is for drum solos.