Show up reliably, take responsibility, and conduct yourself well in a professional setting.
Work ethic is the commitment to doing your job well and consistently, including reliability, accountability, and integrity. Professionalism is how that commitment shows up in your conduct, communication, and appearance in a workplace context.
Being someone people can count on to show up and deliver, even on unglamorous tasks.
Owning your mistakes directly instead of making excuses or shifting blame.
Doing the right thing (accurate reporting, honest estimates) even when no one is checking.
Communicating professionally in emails and meetings, and respecting others' time and boundaries.
During an internship, you accidentally pushed a config change that took down a staging environment for two hours.
You immediately flagged it to your manager yourself before anyone noticed, rolled back the change, wrote a short note on what caused it and how you would prevent it, and your manager specifically praised the way you handled the mistake in your review.