lieutenant

noun

1.
a commissioned military officer
Derived from:
lieutenancy
2.
an officer in a police force
police lieutenant
Derived from:
lieutenancy
3.
an assistant with power to act when their superior is absent
deputy
Derived from:
lieutenancy
4.
an officer holding a commissioned rank in the United States Navy or the United States Coast Guard; below lieutenant commander and above lieutenant junior grade
Derived from:
lieutenancy