To be entitled to, as a result of past actions; to be worthy to have.
"After working tirelessly on the project all week, she truly deserves a well-deserved day off."
In plain English: To deserve something means you have done good enough to earn it fairly without having to ask for it.
"She really deserves a promotion after working so hard for years."
Usage: Use deserve with an infinitive verb or noun phrase to indicate that someone is rightfully rewarded or punished based on their specific behavior. Avoid confusing it with "deserve" used for physical attributes unless those traits directly resulted from the person's own choices.
The word entered English via the Old French deservir and originally meant to serve or work for someone under a master's command. Over time, this sense of serving shifted in meaning so that it now refers to earning something as a reward for one's actions.