Hollow-hearted is an adjective that typically describes a person who lacks feeling, depth, or sincerity. Other synonyms for hollow-hearted include insincere, unfeeling, shallow, callous, insensitive, and indifferent. These words all convey a lack of genuine emotion or empathy. In some cases, an individual may be described as hollow-hearted if they appear to lack moral character or integrity, or if they are only interested in superficial appearances. Regardless of the precise connotations, all of these terms suggest a fundamental shallowness or hollowness in the person described, indicating a lack of true emotional depth or substance.