(literally, agriculture) To make hay during favourable (dry) weather. / (idiomatic) To act while an opportunity exists; to take action while a situation is favorable.

A large number of people co-operating can perform tasks easily.

noisy, opinionated people are often ignorant.

(ethics) A wrongful action is not a morally appropriate way to correct or cancel a previous wrongful action.

(idiomatic) To improvise continuously.

One instance of an event (such as the arrival of a single bird) does not necessarily indicate a trend.

(idiomatic) Diversity is essential: the world would be incomplete if everyone were alike; an expression of surprise at a person or people's eccentricity.

To take a decision that will have personally adverse consequences.

Alternative form of one swallow does not a summer make

A person's circumstances are normally the result of their own actions.