up against it 这个短语是 "up against something" 的强调形式，意思是“面临巨大困难”、“处境极其艰难”或“压力很大”，通常指被严峻的挑战或紧迫的情况所逼迫。 例句： With two key players injured and the final match tomorrow, the team is really up against it. （两名主力队员受伤，明天又是决赛，这支队伍真是处境艰难。） I'm up against it this week—I have three reports to finish by Friday. （我这周压力山大——周五前要完成三份报告。）