What's the difference between a proverb and an idiom? [closed]

An idiom is an expression that can be understood only as a whole and not by analysing its constituent parts. For example, if you know what ‘kick’, 'the’ and ‘bucket’ mean, that won’t help you understand that ‘kick the bucket’ means ‘die’. A proverb may or may not be idiomatic, but it expresses succinctly some form of philosophy, folk wisdom or advice. 'Hindsight is always 20:20' is neither an idiom nor a proverb, but a trite expression of the obvious.

Idioms are short arrangements of words that have a meaning beyond their literal. They can be completely different from their literal meaning, such as "bite the bullet", or "step up to the plate", both of which mean "begin a difficult task." Or they can mean close to their literal meaning, but carry lots of cultural baggage along with them, such as "land of the free" which means what it says, but carries lots of American patriotic baggage, or "tea and sympathy" which denotes a rendezvous with a particular goal of commiseration in mind.

A proverb is, instead, a short or pithy remark or story designed to convey a moral or practical message. It comes from the eponymous book of the Bible which, in many chapters, has pages and pages of one or two verse statements of that kind. "Better to meet a bear robbed of her cubs than a fool in his folly", "A fool and his money are soon parted." etc.

Proverbs are usually pretty literal in their meaning, and are certainly not restricted to those from the Bible, though that is the origin of the name and the form as used in English. Some non-Biblical proverbs would be "many hands make light work", "procrastination is the thief of time", etc.

A proverb is usually a sentence that evokes a sense of wisdom. While most of the time it can refer to a certain sense of wisdom, proverbs are mere expressions of truth based on common sense or practicality.

Ex Once bitten, twice shy.

Carpe diem!

When the cat is away, the mouse will play.

An idiom is a string of words that when taken together has a meaning different to its literal interpretation. The meaning should be taken figuratively.

Example

To keep one's head above the water= to manage a situation