The definition of commitment is:
1) the state or quality of being dedicated to a cause, activity, etc.
"the company's commitment to quality"
2) an engagement or obligation that restricts freedom of action.
In order to be committed, you need to say no to other things. It's about choosing what you want, and at the same time, what you don't want. Deciding and making a decision. Not keeping your options open.
Committed people constantly make new goals and are always striving to push their boundaries and achieve more. People who are committed work hard out of habit and out of loyalty. They have a unique endurance that allows them to physically keep going because they are mentally wired to work endlessly toward their dreams.
How to show your commitment at work
Committed employees bring added value to the organisation, including through their determination, proactive support, relatively high productivity and an awareness of quality. Employees' being comitted to work are also less likely to call in sick or to leave the organisation.