From un- + derivatized. <span class="searchmatch">underivatized</span> Not derivatized...
underivatised (not comparable) Alternative form of <span class="searchmatch">underivatized</span>....
(comparative more derivatized, superlative most derivatized) (organic chemistry) modified by the formation of a derivative nonderivatized <span class="searchmatch">underivatized</span>...