non-removable

adjective

1. that may be removed.
2. Mathematics.
   1. (of a singularity of a function of a complex variable) noting that the function is not analytic at the point but that the function can be redefined so as to be analytic at the point.
   2. (of a discontinuity) noting that the function is discontinuous at the point but that the function can be redefined so as to be continuous at the point.Compare essential(def 5).

adj.1530s, from remove (v.) + -able. Related: Removability.