Many idiomatic expressions, in their original use, were not figurative but had literal meaning. For instance, spill the beans (meaning to reveal a secret) has been said to originate from an ancient method of democratic voting, wherein a voter would put a bean into one of several cups to indicate which candidate he wanted to cast his vote for. If the jars were spilled before the counting of votes was complete, anyone would be able to see which jar had more beans, and therefore which candidate was the winner. Over time, the practice was discontinued and the idiom became figurative.
Some idioms are transparent. Much of their meaning does get through if they are taken (or translated) literally. For example, lay one's cards on the table meaning to reveal previously unknown intentions, or to reveal a secret. Transparency is a matter of degree; spill the beans (to let secret information become known) and leave no stone unturned (to do everything possible in order to achieve or find something) are not entirely literally interpretable, but only involve a slight metaphorical broadening.
Find below a list of common Idioms:
1. ‘Once in a blue moon’ means an event that happens infrequently.
2. To "call it a day" means to decide to stop working for the day.
3. ‘Speak of the devil’ means that the person you’re just talking about actually turns up at that moment.
4. ‘When pigs fly’ means something that will never happen.
5. "In a nutshell" means in a few words.
6. If a decision is really obvious or really easy to make, the decision is a "no brainer. "
Doubts on this article