Section 2(1)(w) in The Border Security Force Act, 1968
(w)"superior officer", when used in relation to a person subject to this Act, means,-(i)any member of the force to whose command such person is for the time being subject in accordance with the rules;(ii)any officer of higher rank or class or of a higher grade in the same class, and includes when such person is not an officer, a subordinate officer or an under-officer of higher rank, class or grade;(x)"under-officer" means a Head Constable, Naik and Lance Naik of the Force;