specialist

ot noun

1. An organism that is specialized for a particular environment. The tree Lepidothamnus laxifolius is a high alpine specialist found in high-altitude bog communities and in scrub.
2. Someone who is an expert in, or devoted to, some specific branch of study or research.
3. A physician whose practice is limited to a particular branch of medicine or surgery.
4. Any of several non-commissioned ranks corresponding to that of corporal.

sifat adjective

1. Specialised.