noun, na-adjective, noun which may take the genitive case particle 'no'
self-righteous; smug; self-satisfied; complacent
Describes a person who is convinced of their own correctness or superiority, often ignoring others' opinions. Can be used as a noun or adjectivally (な-adjective or の-adjective).
彼の独りよがりな態度にはうんざりだ。
I'm fed up with his self-righteous attitude.
独りよがりの考え方では、チームでうまくやっていけない。
With a self-centered way of thinking, you can't get along well in a team.
Alternate kanji spelling using 善 (good/virtue), implying self-righteousness.