the ability and tendency to determine what should be done and to start doing it without instruction
to start something
The exact meaning of starting something depends upon the context. For example:
"She did it on her own initiative." — started it without anyone telling her to
"She seized the initiative." — started actions that force others to react to her rather than her having to react to them
"the peace initiative" — a plan or the start of actions to bring about something
"a ballot initiative" — a proposed law that is started by citizen petition rather than by the legislature (applicable in many jurisdictions such as California)
Petty Officer Wasdin's exceptional professional ability, initiative, and loyal devotion to duty reflect great credit upon himself and the United States Naval Service.
By his superb initiative, courageous action, and complete dedication to duty, Petty Officer Wasdin reflected great credit upon himself and upheld the highest tradition of the United States Naval Force.
There are no more uses of "initiative" in I Am a Seal Team Six Warrior.