unsolicited
adj.not asked for and often not wanted. You use this to describe things like advice or emails that arrive when you did not request them.
adj.given or supplied without being requested or invited. Often carries a negative connotation of being intrusive or unwelcome.
“I keep getting unsolicited emails from companies I don't know.”
“She found it difficult to stay polite when her neighbors offered unsolicited advice on how to raise her children.”
“The legal department warned that accepting unsolicited manuscripts could expose the publishing house to future claims of intellectual property theft if a similar story were later developed internally.”
Typically used attributively before a noun; frequently collocates with 'advice', 'feedback', or 'commercial email'.
“Photograph: Darren England/AAP A crackdown on gambling advertising will include a ban on ads on all NSW government and council-owned assets, as well as a ban on unsolicited direct marketing to potential customers.”
“Sick of getting unsolicited beauty tips on social media, the Danish prime minister, Mette Frederiksen , rebuffed a male cosmetic surgeon’s offer to “fix” her and advised women in similar situations to embrace self-acceptance.”
From un- + solicited.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.