Grinding mobs in the starter zone to max level takes several days.
Tips
usage
满 (mǎn, 'full') + 级 (jí, 'level') = 'level cap'. Used as both adjective ('your character IS 满级') and verb-resultative ('grind to 满级'). Compare related: 升级 (shēngjí, level up), 等级 (děngjí, character level), 满血 (mǎnxuè, full HP).
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Now used metaphorically outside gaming: 满级人类 (mǎnjí rénlèi, 'max-level human') is internet slang for someone who has fully optimized something or is too capable for the situation. Tied to gamer culture but understood by non-gamers.