ineffectual

Ineffectual means trying hard and achieving nothing. The effort is real; the result is not.

That is what separates it from ineffective. An ineffective drug simply does not work, and no one blames it. An ineffectual person is doing their best and it is not enough, which makes the word quietly cruel — an ineffectual manager, an ineffectual protest, an ineffectual wave at a departing bus. It is a favourite of novelists for exactly that reason, since it damns somebody without ever accusing them of laziness. The adverb is ineffectually, and it usually follows a verb like flapped or gestured.