ability to take action; ability to take initiatives; energy; dynamism; drive
彼女は行動力があって頼れる存在だ。
She has initiative and is someone you can rely on.
行動力のある人はチームを動かす力を持っている。
A person with initiative has the power to move a team.
夢があっても行動力が伴わないと実現は難しい。
Even if you have a dream, without the drive to act it is hard to make it real.