Synonyms of 'smug'
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A complacent person is very pleased with themselves or feels that they do not need to do anything about a situation, even though the situation may be uncertain or dangerous.
We cannot afford to be complacent about our health.
If you describe someone as holier-than-thou, you disapprove of them because they seem to believe that they are more religious or have better moral qualities than anyone else.
those with holier-than-thou attitudes
Thesaurus for smug from the Collins English Thesaurus
If you say that someone is smug , you are criticizing the fact they seem very pleased with how good, clever , or lucky they are.