a. 不败的, 无瑕的

Indefectible \In`de*fect"i*ble\, a. [Pref. in- not + defectible:
cf. F. ind['e]fectible.]
Not defectible; unfailing; not liable to defect, failure, or
decay.

An indefectible treasure in the heavens. --Barrow.

A state of indefectible virtue and happiness. --S.
Clarke.