From underthink + -er. <span class="searchmatch">underthinker</span> (plural <span class="searchmatch">underthinkers</span>) One who underthinks....
<span class="searchmatch">underthinkers</span> plural of <span class="searchmatch">underthinker</span>...
gives us plenty of opportunity to overthink — or underthink — the problem, and this is where we really start to bollix things up. overthink <span class="searchmatch">underthinker</span>...