from Oxford Dictionaries
Curiosity killed the cat
As the conclusion on a coroner’s report, this might be less than convincing – curiosity would have had to wipe out all nine lives of a cat, for starters – but idiomatically, it is of more use. The expression is a warning that being too inquisitive is likely to get you into trouble. It should also be heeded by any cats wandering around Mars.
No room to swing a cat
When I’m organizing my living arrangements, my primary concerns run along the lines of “Are there enough cupboards in the kitchen?” or “Is there room for fourteen bookcases?” Swinging cats seems to be me a singularly profitless use of time, but (it turns out) this expression – which simply denotes a confined space – refers to cat in the sense of cat-o’-nine-tails – that is, a whip once commonly used by sailors.
Has the cat got your tongue?
This idiomatic question – posed to someone remaining silent when they should be speaking – is one of those which, if you think about it, is rather more unpleasant than you might imagine. Also in this category: ‘touched a raw nerve’ and ‘keep your eyes peeled’. Sorry for making you wince.
Like a cat on a hot tin roof
A wonderfully evocative image, this simile is used to express agitation or anxiety. In British-English, a variant is like a cat on hot bricks. It also, of course, gave rise to the Pulitzer-prizewinning Tennessee Williams play Cat on a Hot Tin Roof (1955).
[Put the] cat among the pigeons
As well as being the title of an Agatha Christie novel, this British-English idiom is used to describe saying or doing something controversial – indeed, something (to continue the ornithological trope) that is likely to ruffle feathers. Having spent time in pigeon-filled parks, I don’t fancy the chances of the average moggy against a flock of pigeons. Most of the felines of my acquaintance would far rather have a gentle nap than rage against the flying of the birds.
I’m more nervous than a long tailed cat in a room full of rocking chairs (my favorite).