ineffectual
adjective formal uk/ˌɪn.ɪˈfek.tʃu.əl/ us/ˌɪn.ɪˈfek.tʃu.əl/
无能力的；不起作用的，无效果的
not skilled at achieving, or not able to produce, good results
an ineffectual leader 无能的领袖
The teachers were ineffectual at maintaining discipline. 这些老师无力维持纪律。
Synonym: unavailing
Compare: ineffective