1
general::
Found to be lacking something one needs, especially money, as in Can you pay the check? I seem to be caught short. This idiom uses short in the sense of "lacking money," a usage dating from the early 1500s.
American Heritage Idioms
2
general::
Phrase(s): caught short
1. left without any money temporarily. • I’m caught a little short. Can I borrow a few bucks? 2. pregnant and unmarried. • Both of Jane’s sisters got caught short before they graduated high school.
McGrawhill's American Idioms And Phrasal Verbs