IPA: //hæfˈhɑːrtɪdnəs//
KK: /ˈhæfˈhɑrtɪdnəs/
The quality of showing little enthusiasm or effort in something.
Her halfheartedness in the project was evident, as she didn't put in much effort.
Halfheartedness → It is formed from "half" (from Old English "healf", meaning part of something) and "hearted" (from "heart", which comes from Old English "heorte", meaning the organ associated with emotion and spirit) combined with the suffix "-ness" (meaning the state or quality of). The word describes the state of having only a part of one's heart or spirit engaged in something, indicating a lack of full commitment or enthusiasm.
Think of 'half' meaning part and 'hearted' relating to the spirit or emotion — this helps you remember that halfheartedness means a lack of full commitment or enthusiasm.