IPA: /ˈlɔːŋɪŋli/
KK: /ˈlɔŋɪŋli/
In a way that shows a strong desire or wish for something that is often unattainable.
She looked longingly at the beautiful house across the street.
Longingly → It is formed from "long" (from Old English *lang*, meaning having a great duration or extent) and the suffix "-ly" (meaning in a manner of). The word "longingly" describes the manner of having a strong desire or yearning for something over a prolonged period.
Think of the word 'long' to remember that 'longingly' means to desire something deeply and for a long time.