noun
senior officer
A military term referring to an officer of higher rank or longer service, often in a command or supervisory role.
先任将校が部隊の指揮を執った。
The senior officer took command of the unit.
上級将校 emphasizes higher rank, while 先任将校 emphasizes seniority in service or appointment.
Compound of 先任 (seniority, prior appointment) and 将校 (commissioned officer).