Dua Qunoot is the supplication that we generally say in the Witr prayer:
‘O Allah, guide me along with those whom You have guided, pardon me along with those whom You have pardoned, be an ally to me along with those whom You are an ally to and bless for me that which You have bestowed. Protect me from the evil You have decreed for verily You decree and none can decree over You. For surety, he whom you show allegiance to is never abased and he whom You take as an enemy is never honoured and mighty. O our Lord, Blessed and Exalted are You.’
Shaikh Ibn Uthaimeen (rahimahullah) wrote a wonderful, easy-to-understand explanation of this dua which you can read here.
Also, the translators, may Allah reward them greatly, have added a word-to-word translation of this dua.
I think we should all read and ponder over this explanation so that when the Imam says this dua, we can say “Ameen” from our hearts and not just mindlessly chirp it.