There are several synonyms for the term "conscience-stricken," including remorseful, guilt-ridden, regretful, penitent, contrite, and shamefaced. All of these terms signify a strong sense of regret or remorse over one's actions or decisions. Remorseful and regretful convey a deep feeling of sorrow for past behaviors, while penitent and contrite suggest a desire to atone and seek forgiveness. Shamefaced implies a sense of embarrassment or humiliation that results from acting against one's own moral code. These words all convey the same basic idea of a troubled conscience, indicating that the speaker has done something wrong and is feeling the weight of their actions on their conscience.