complacent
adj.adj. feeling so satisfied with your own success or situation that you stop trying to improve. It is often used as a warning because this feeling can lead to lazy mistakes.
adj. showing uncritical satisfaction with oneself or one's achievements, often accompanied by an unawareness of actual dangers or deficiencies. Typically used predicatively after linking verbs or attributively to describe an attitude.
We cannot become complacent just because we are winning.
The company became complacent after years of market dominance and failed to notice its competitors catching up.
Success often breeds a complacent attitude in established institutions, making them vulnerable to more agile and innovative startups that are still hungry for growth.
Borrowed from Latin complacēns (“very pleasing”), present participle of complacēre (“to please at the same time, be very pleasing”), from com- (“together”) + placēre (“to please”); see please and compare complaisant.
Often follows linking verbs like 'become', 'get', or 'remain'. Frequently takes the preposition 'about' to indicate the subject of the satisfaction.