From un- + forewarned. <span class="searchmatch">unforewarned</span> (comparative more <span class="searchmatch">unforewarned</span>, superlative most <span class="searchmatch">unforewarned</span>) Not forewarned....
From Middle English forwarned, equivalent to forewarn + -ed. forewarned simple past and past participle of forewarn forewarned is forearmed <span class="searchmatch">unforewarned</span>...