Lieutenant

[Sarah]

A mid-level commander/officer rank in many modern military forces. It can also be used to refer to a second-in-command in military or political hierarchy.

[Britney]

a low level [U.S. military] officer in the Air Force, Army and Marines. Officer ranks (which operate separately from enlisted ranks) are categorized as O- A [Lieutenant] is an O-1 or O-2. Only in the navy is this different where a Lt. is an O-2 or O-3. In Contrast a General or Admiral is an O-10.
The term can also be applied in civilian terms to refer to a second in command. As in a [lieutenant] governor.

[Sommer]

A [rank] of person in the [military] that [frequently] gets lost and is usually very confused.

[Hina Muqadas]

A deputy or substitute acting for a superior.