Form of discrimination (6)
I believe the answer is:
ageism
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">form of discrimination</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ageism that I've seen before include "Discrimination against the elderly" , "Resentment of the more experienced" , "Bad attitude to the grey" , "discriminating against the elderly?" , "The practice of treating people differently on the basis of longevity" .)