{adj. phr.}, {informal} Faced with a great difficulty or problem; badly in need. * /The Smith family is up against it because Mr. Smith cannot find a job./ * /You will be up against it if you don't pass the test. You will probably fail arithmetic./ Compare: HARD UP, END OF ONE'S ROPE, BACK TO THE WALL(2).
UP AGAINST IT
Meaning of UP AGAINST IT in English
Slang English vocab. Английский сленговый словарь. 2012