C1 adjective /ˌɪn.ɪˈfɛk.tʃu.əl/
ineffectual
inefficace
Meaning
Not producing any or the desired effect; lacking the ability or qualities to achieve a purpose.
Example
The manager’s ineffectual leadership caused the team to lose motivation.
Le leadership inefficace du manager a causé la perte de motivation de l'équipe.