unjustifiable       
adjective uk/ʌnˌdʒʌs.tɪˈfaɪ.ə.bəl/ us/ʌnˌdʒʌs.təˈfaɪ.ə.bəl/
 不可接受的;无理的;无正当理由的
unacceptable and wrong because there is no good or fair reason for it
  His behaviour was unjustifiable. 他的行为毫无道理。 
 unjustifiable expense 毫无道理的开销 
 Synonyms: indefensibleunwarranted 
Opposite: justifiable