For the word denigrate its a verb? How do I find the exact etymology help first yr english I'm giving presentation

Question

anonymous · Answer

I found this on Dictionary.com- I would use this as a reference point and go backwards from there.  I don't know if you have actually sat and attempted to read a Dictionary but I have.  I found it to be useful in the explanation of words, origination and how over different time spans they have change them in the actually English language.  Boring as Hell but informative.  I hope this helps

anonymous · Answer

denigrate 
1526, from L. denigratus, pp. of denigrare "to blacken, defame," from de- "completely" + nigr-, stem of niger "black," of unknown origin. "Apparently disused in 18th c. and revived in 19th c." [OED].