Professionally means doing something with the skill, care, and standards expected of someone who does that work for a living. When a carpenter builds a deck professionally, it's sturdy, level, and looks great because they know exactly what they're doing. When someone behaves professionally at work, they're punctual, prepared, and treat others with respect.

The word also describes work you do as your profession or career, the way you earn money. A professional athlete plays sports professionally, meaning it's their job, not just a hobby. A musician who performs professionally gets paid for concerts, while someone who plays guitar just for fun at home is an amateur.

You can act professionally even as a student. When you complete an assignment carefully, meet your deadlines, and communicate clearly with your teacher about any problems, you're working professionally. When a student council representative listens to different viewpoints before making a decision, they're behaving professionally.

The opposite would be doing something sloppily, carelessly, or in an unprofessional way: showing up late without explanation, doing messy work, or treating people rudely. Acting professionally means taking your responsibilities seriously and doing your best work, whether you're getting paid for it or not.