Meaning of “professional” - Learner’s Dictionary

professional

adjective uk us /prəˈfeʃənəl/
JOB [ always before noun ]

B2 relating to a job that needs special training or education:

You should get some professional advice about your finances.
EARNING MONEY

B1 Someone is professional if they earn money for a sport or activity that most people do as a hobby:

a professional athlete/musician
a professional golf championship
→ Opposite amateur adjective
SKILL

B1 showing skill and careful attention:

a professional attitude
He looks very professional in that suit.
→ Opposite unprofessional

(Definition of “professional adjective” from the Cambridge Learner’s Dictionary © Cambridge University Press)