Aside from the actual rank and branches it belongs to, a 2nd Lieutenant can be described as a person in any branch of the armed forces across the world in a position equivalent to a commissioned officer of sorts, or any form of leadership.

A 2nd Lieutenant is a person who, while their rank or title does display leadership, their lack of experience does not (As for most militaries, you can be young and still be commissioned to be trained as an officer and immediately placed at the rank of 2nd Lieutenant, or something similar).

Someone described as a 2nd Lieutenant can be a person who thinks they know what they're doing or that they're better than everyone else, often going by the mentality of "Respect is given immediately because of my rank", when clearly it's not. A 2nd Lieutenant can also be described as someone who just lacks leadership or is incompetent at their job. Last, a 2nd Lieutenant can be someone who has the experience, but bosses around people they've barely worked with, usually with little concern for their thoughts on the matter.