A heavy heart is a feeling of deep sadness or GRIEF. GRIEF, which has five letters, is an intense emotional suffering caused by loss. DOLOR, also with five letters, is a deep sorrow or anguish. BATHOS, with six letters, is an emotion that is overly sentimental or melodramatic. HEARTBREAK, with ten letters, is the intense emotional pain caused by the loss of a loved one. Bleedingheart, with thirteen letters, is a term used to describe someone who is overly sympathetic or sentimental. All of these terms are related to the phrase 'heavy heart' and can be used to describe the feeling of deep sadness or GRIEF.