From self- + flattery.
self-flattery (uncountable)
- The holding of an unjustifiably high opinion of oneself or one's actions.
2007, Willis Goth Regier, In Praise of Flattery[1]:When self-flattery is turned up high it gets your adrenaline pumping, it rivets your attention.
2010, Albrecht Classen, Friendship in the Middle Ages and Early Modern Age[2]:Causing blindness to one's own faults, self-love ultimately generates self-flattery, according to Plutarch's discussion.
2016, Boyd Bailey, Two Minutes in the Bible Through Psalms[3]:Self-flattery is foolish.