The antonyms for the phrase "giving all one's got" can be varied and include words like half-hearted, apathetic, indifferent, lackadaisical, lethargic, lazy, and unmotivated. These words describe the opposite of the act of showing commitment, dedication, perseverance, and enthusiasm towards a task. When someone is putting in less than their full effort or showing a lack of interest, they are exhibiting the opposite of "giving all one's got." It is essential to identify these antonyms and work towards overcoming them to achieve success and reach our full potential in life.