A soft-fork activation method where economic nodes enforce new rules at a set time, pressuring miners to comply.
In a UASF, exchanges, wallets, and users upgrade to software that enforces new rules starting at a predetermined time or block, regardless of miner signaling. If enough economic weight adopts the rules, miners follow to avoid producing invalid blocks.
"During the SegWit activation debate, BIP148 proposed a UASF to enforce SegWit rules, catalyzing miner support prior to the activation deadline."
All terms and definitions may update as the Cryptionary improves.