IPA: /ˈhæfˈhɑːtɪd/
KK: /ˈhæfˈhɑrtɪd/
Showing little interest or effort; not enthusiastic or committed.
Her halfhearted attempt to clean the house left it still messy.
Halfhearted → It is formed from "half" (from Old English "healf", meaning part of something) and "hearted" (from "heart", meaning the center of emotion or spirit). The word "halfhearted" describes an attitude that is only partially committed or lacking enthusiasm, as if one’s heart is only half in it.
Think of being only "partially" committed ('half') and not fully engaged ('hearted') — that's what halfhearted means.