complacency
definition
a feeling of satisfaction with oneself or achieved goals that can lead to a lack of awareness of potential dangers or deficiencies
example
His complacency after achieving the promotion blinded him to the challenges that lay ahead, making him underestimate his competitors.
synonyms
self-satisfactionsmugnesscontentment
word origin — from Latin 'complacere' meaning 'to please very much, to please entirely'