1
general::
Very little space, cramped quarters, as in There's not enough room to swing a cat in this tent. This expression, first recorded in 1771, is thought to allude to the cat-o'-nine-tails, or "cat," a whip with nine lashes widely used to punish offenders in the British military.
American Heritage Idioms
2
general::
Phrase(s): not enough room to swing a cat
Rur. not very much space. • Their living room was very small. There wasn’t enough room to swing a cat. • How can you work in a small room like this? There’s not enough room to swing a cat.
McGrawhill's American Idioms And Phrasal Verbs