From un- + adventitious. <span class="searchmatch">unadventitious</span> (comparative more <span class="searchmatch">unadventitious</span>, superlative most <span class="searchmatch">unadventitious</span>) Not adventitious....
unadumbrated unadvanced unadvancement unadvancing unadvantaged unadvantageous <span class="searchmatch">unadventitious</span> unadventured unadventuresome unadventuring unadventurous unadversarial...