inexperienced       
adjective uk/ˌɪn.ɪkˈspɪə.ri.ənst/ us/ˌɪn.ɪkˈspɪr.i.ənst/
B2 缺乏经验的,不熟练的
having little knowledge or experience
  They are young inexperienced parents and need support. 他们是些缺乏经验的年轻父母,需要得到帮助。 
 Synonym: green (NOT EXPERIENCED) 
Opposite: experienced