unwanted, gratuitous, unasked, dispensable, unlooked-for, unbidden, unnecessary, unasked for, redundant, undesired, superfluous, uninvited, unsought, undesirable.
But the bitter complaints about its injustice are unsolicited
testimony to its efficacy.
One who is in the habit of giving unsolicited
advice is likely to take for granted that his advice has been acted upon, even though experience should teach him that this is seldom the case.
You speak of presumption in others, Mr. Renault, and, unsolicited,
you offer an affront to me and to a gentleman who is not here to answer.