"Fink out" means to back out or fail to keep a promise. When looking for antonyms for this phrase, we can consider words that imply showing up, following through, or being dependable. Some possible antonyms are "show up," "deliver," "commit," "persevere," "keep faith," "stay loyal," and "stick to one's word." These words connote trustworthiness, perseverance, and dependability. To avoid finking out, individuals must make sure to commit to their promises, show up as expected, and follow through with their commitments. People who possess these traits are more likely to build and maintain successful relationships, both personally and professionally.