- A person who plays a musical instrument.
- Can play one or more instruments.
- May or may not be able to read music.
- May or may not have formal musical training.
- May or may not perform music as their primary occupation.
Musician:
- A person who is skilled in the art of music.
- May play one or more instruments, but may also be a singer, composer, conductor, arranger, etc.
- Can read music and has formal musical training.
- Performs music as their primary occupation.
In summary, an instrumentalist is someone who plays a musical instrument, while a musician is someone who is skilled in the art of music and performs music as their primary occupation.