Widespread therapeutic and commercial interest in recombinant mucin technology has emerged due to the unique ability of mucin glycoproteins to hydrate， protect， and lubricate biological surfaces. However， recombinant production of the large， highly repetitive domains that are characteristic of mucins remains a challenge in biomanufacturing likely due， at least in part， to the inherent instability of DNA repeats in the cellular genome. To overcome this challenge， we exploit codon redundancy to encode desired mucin polypeptides with minimal nucleotide repetition. The codon-scrambling strategy was applied to generate synonymous genes， or "synDNAs，" for two mucins of commercial interest: lubricin and mucin 1. Stable， long-term recombinant production in suspension-adapted human 293-F cells was demonstrated for the synonymous lubricin complementary DNA (cDNA)， which we refer to as SynLubricin. Under optimal conditions， a 293-F subpopulation produced recombinant SynLubricin at more than 200?mg/L of media and was stable throughout 2 months of continuous culture. Functionality tests confirmed that the recombinant lubricin could effectively inhibit cell adhesion and lubricate cartilage explants. Together， our work provides a viable workflow for cDNA design and stable mucin production in mammalian host production systems.