Lose heart is the feeling of losing confidence or hope in a certain situation. Its synonyms include demoralized, disheartened, discouraged, and crestfallen. Demoralized refers to feeling defeated or overwhelmed, whereas disheartened is feeling a loss of enthusiasm. Discouraged means feeling a lack of motivation or determination. Crestfallen suggests feeling dejected, downcast or defeated. Other synonyms for lose heart include despondent, hopeless, and forlorn, which imply a sense of depression and sadness. Whenever one feels discouraged or disheartened, it's important to remember that it's only temporary, and that perseverance and positive thinking can help regain hope and confidence.