polite and courteous; exceedingly respectful
Describes a very formal, elaborate politeness, often with a nuance of being overly or stiffly courteous. Used for behavior, speech, or attitude.
His excessively polite manner made me feel distant instead.
They exchanged greetings with elaborate courtesy.
丁寧 is the standard word for 'polite' or 'careful'. 慇懃丁重 is much more formal and often implies an almost excessive level of politeness.
慇懃 alone also means 'courteous' but can carry a negative nuance of being overly familiar or insincere. 慇懃丁重 is more straightforwardly about extreme politeness.
A compound of 慇懃 (いんぎん, 'courteous') and 丁重 (ていちょう, 'polite, respectful'). Both parts reinforce the idea of deep politeness. The exact historical derivation is uncertain, but the combination is used to emphasize an especially high degree of courtesy.