The phrase 'with no heart' refers to someone or something that is cold, unfeeling, or lacking in compassion. Some synonyms for this phrase might include heartless, cruel, callous, unemotional, merciless, or devoid of empathy. Other words that convey a similar meaning include inhumane, pitiless, ruthless, and insensitive. These terms can be used to describe people who are indifferent to the suffering of others, or to describe situations or actions that are cold and unforgiving. Overall, the phrase 'with no heart' is a powerful and evocative way to describe those who lack empathy and compassion, and the various synonyms for this phrase help to capture the full range of emotions and attitudes that this concept implies.