The phrase "went back on one's word" means to break a promise or fail to keep a commitment. The antonyms for this phrase might include reliable, trustworthy, dependable, honest, and faithful. These are all qualities that describe someone who keeps their word and follows through on their commitments. Antonyms for "went back on one's word" might also include words like keep, honor, uphold, or adhere. By keeping one's promises and commitments, people build trust and credibility, which are important qualities in personal and professional relationships. Breaking promises or going back on commitments can damage those relationships and erode trust over time.