ineffectual
adj. C1 Advanced US //ˌɪnəˈfɛktʃuəɫ// UK //ɪnɪfˈɛktʃuːəl// in·ef·fec·tu·al
adj. not having any real effect or power. You use this to describe someone or something that fails to do what it is supposed to do.
adj. lacking the power or effectiveness to produce a desired result. Often used to describe individuals or policies that fail to achieve their intended purpose.
The new law proved to be ineffectual in reducing crime.
Despite the team's best efforts, the ineffectual leadership led to a complete failure of the project.
The critic argued that the protagonist's ineffectual attempts to change the system only served to highlight the deep-seated corruption within the establishment.
From in- + effectual.